If there's one company that knows a thing or two about performance, it's GM. Once the world's largest company, the behemoth acquired the loyalty of its customers by producing some of the greatest performance vehicles of the 20th century. The GTO, Camaro, Corvette, Chevelle, Grand National, and so many others dominated the racetracks and the city streets from sea to shining sea, and when the turn of the millennium finally rolled around, the company wasn't planning on slowing down anytime soon.The company went full steam ahead into performance with an onslaught of models in every price bracket. We're talking hot hatches, retro sport trucks, luxury grand tourers, massive V8-powdered SUVs, and more, under every brand and badge the company offered, and while some of them went on to become legends, not every model was a hit. A few that made it through were peculiar at best, and downright bizarre at worst, and we've compiled 10 of the strangest that sometimes prove an old dog can learn new tricks.The 10 strange GM performance models below were all chosen due to their unconventional design and characteristics, and not because they were necessarily bad vehicles. They've then been ordered from oldest to newest according to their first model year. Chevrolet SSR Model Years: 2003-2006 2003-2006 Chevrolet SSR Top Down Blue Front Angled ViewThe first vehicle on the list is easily one of the weirdest, even if it does have a special place in our hearts. When it was unveiled at the 2000 Detroit Auto Show, the Super Sport Roadster was the talk of the town, and everyone was clamoring for a production version to hit dealer lots. Designed with heavy influence from the 1940s GM Advance Design vehicles, it was a striking vehicle, one that GM promised would pack the performance to match.However, it sat on a modified version of the GMT360 platform, which didn't give it a great starting point, and GM initially made the misguided decision of only offering it with the 5.3-liter Vortec V8 and a 4-speed automatic. Buyers were turned off, and two years later, the much more competitive 6.0-liter LS2 V8 and a manual transmission were offered to remedy the situation. However, the damage was done, and after just four years on sale, it was canned. Saturn Ion Red Line Model Years: 2004-2007 2003 Saturn Ion Red Line Blue High Front Angled ViewWhen GM was throwing around money for performance models, every brand wanted a piece of the pie, even the historically economical and quirky Saturn. The division came up with the Red Line performance line, which would go on to be featured on three different models, and one of the first was the Ion quad coupe. The "quad coupe" part of its name came from its unconventional door set that featured a clamshell design for easier rear seat access.The rest of the vehicle was given a sportier makeover, and a supercharged inline-four cranking out 205 horsepower sat under the hood. Power delivery was linear, and you were able to get that power down to the ground with relatively little fuss, but the odd looks and overall cheapness did little to attract buyers to its cause. Saturn Vue Red Line Model Years: 2004-2007 2004 Saturn Vue front 3/4 parked angledThe Saturn Vue was a pretty basic SUV, all things considered, but the first-generation Red Line actually hid a Japanese secret under the hood. Thanks to a partnership between GM and Honda, the hopped-up Vue was offered with a 3.5-liter Honda V6, which was shared at the time with vehicles like the Acura MDX and Honda Odyssey.It was a stout powertrain, known for its reliability and impressive power, and, combined with the Vue's unconventional looks, it made for a very interesting performance SUV option, particularly when paired with its loud Lime Green paint. However, dealers struggled to sell the models to customers who were understandably confused about why GM would grab a V6 from a competitor when it had about seven in its stable at the time, and after one generation, the partnership ended. Pontiac Grand Prix GXP / Chevrolet Impala SS Model Years: 2005-2008 2005 Pontiac Grand Prix GXP Gray Front Angled ViewA sports sedan from GM is usually a great idea, but these two options introduced in the early 2000s are easily some of the weirdest of all time. The recipe wasn't bad: take two W-platform cars, shove a V8 under the hood, tighten up the suspension, and send them on their way. However, the one major caveat was that both of these vehicles were front-wheel drive, and, to this day, they exist as the only FWD sedans ever produced by either brand to be offered with V8s.Performance-wise, they were fine, but the Impala was certainly hurt by its common-traffic styling. The Grand Prix looked and drove better, and a big part of this was the staggered tire setup that actually offered wider wheels in the front (8-inch) compared to the rear (7-inch). Crazy stuff. Saab 9-2X Aero Model Years: 2005-2006 2005 Saab 9-2x Silver Front Angle DrivingWe had to include the "Saabaru" on this list. For those unaware, in the early 2000s, Saab felt it needed to offer a sporty compact car in the US to better compete against its European brethren, and it turned to its owner, GM, to help it out. GM looked around and decided that the best fit would be the Subaru Impreza hatchback, a company it owned a 20% stake in at the time.Saab quickly went to work, drastically changing the look and feel of the vehicle, while ensuring it kept the fun, AWD nature of the donor model. The Aero model was essentially a carbon copy of the WRX underneath, with some firmer suspension thrown in along with the steering rack from the STI. It looked like a Saab and drove like a rally-bred Subaru, and by all accounts, it was a success in reviewers' eyes. Chevrolet Malibu Maxx SS Model Years: 2006-2007 2006 Chevrolet Malibu Maxx SS front 3/4 drivingThe Malibu Maxx was always a weird car, as visually it sat halfway between a hatchback and a fridge, but that didn't stop GM from injecting some performance into the vehicle with the introduction of the Maxx SS. The company took the slightly frumpy-looking vehicle, gave it a bit of a facelift, some sportier wheels, and upgraded its 3.5-liter push-rod V6.The engine was bored out to 3.9-liters and given an advanced variable valve timing system that both helped to push power to 240 horses. All of that power went strictly to the front wheels, and a 4-speed auto was the only transmission option, but reviewers noted the vehicle was still eager, and overall, the changes made the SS the Maxx to get, it you could get past the looks. Cadillac XLR-V Model Years: 2006-2009 2006 - 2009 Cadillac XLR-V front 3/4Have you ever wished your Corvette came with a retractable hard top and a Cadillac badge? No? Well, in the early 2000s, GM thought you might be interested in the concept, which is why it created the XLR grand tourer: a Corvette with an Art and Science Cadillac body, produced on the same lines in Bowling Green, Kentucky.However, even GM thought it deserved a little more differentiation, which is why it forewent an LS in favor of Cadillac's Northstar V8. For the XLR-V, that engine was outfitted with a supercharger, it was given a makeover, and the addition of GM's excellent Magnetic Ride Control for a sportier setup. The result was a capable vehicle, but an extremely expensive one, which is why its sales never amounted to much. Pontiac G6 GXP Street Edition Model Years: 2008-2009 2008 Pontiac G6 GXP front 3/4 black with Street Edition PackageSometimes, designers are out of control. The Pontiac G6 GXP Street Edition is one of those times. The car, at its core, is perfectly fine, offering an impressive 252 horsepower, which made it one of the quickest FWD cars of its time. As this was an era when tuner culture was really enjoying a resurgence, Pontiac felt the G6 GXP could go even further to elevate its looks, and added a "Street Edition" package on coupe and sedan models that pushed the looks over the edge.Look, at its core, the G6 GXP wasn't a conventionally beautiful car, but add in the hood vents and ridiculous "Hammerhead" spoiler, and you now have a childhood doodle come to life. It was extreme, and not in all the right ways, but its outlandish nature is somewhat endearing, as it showed Pontiac wasn't afraid to take big swings. Chevrolet HHR SS Panel Van Model Years: 2008-2010 2009 Chevrolet HHR SS Panel front 3/4 redWhen Chrysler came up with the PT Cruiser, GM was apparently jealously looking on from a distance because soon, it was cooking up a retro hatchback of its own. If they look familiar, it's because they were designed by the same person, Bryan Nesbitt, and we go back and forth on which one we like more.We know that the HHR was quirkier, not only because it was offered as a 260-horsepower, high-performance hatchback, but because this trim even made it on the panel van variant. Yes, in 2009, you could grab a panel van HHR SS with a five-speed transmission, probably so delivery drivers had the option of something a little more exciting. It was weirdly quick, super niche, and one of the most fun factory vans GM ever built. Saab 9-7X Aero Model Years: 2008-2009 2008 Saab 9-7X Aero Exterior Finished In Black frontThe last model on this list is another rebadged Saab, but just like the last time, we actually think GM managed to get it right. It was one of many different vehicles that shared the GMT360 platform, and out of all of them, it's actually our favorite, because it was hiding a powerful secret.For 2008, GM decided to offer a high-performance Aero variant that utilized the same LS2 V8 shared with the Chevy Trailblazer SS, and along with bespoke chassis, suspension, and brake upgrades, it rode much better than many of its siblings. We also think it looks pretty good and that it's aged much better than many of the other variants, like the Isuzu Ascender and Buick Rendezvous. Today, it makes for an interesting used option, because you get that classic American power in a much tidier European package.Sources: GM