Most major auto manufacturers tend to stay in their lane, sticking to what they do best. But every so often, they come up with something that is so far out of their wheelhouse that you wonder how it got the green light for production at all. Sometimes it's a race-bred supercar from a manufacturer better known for its hybrid sedans, like the Lexus LFA. Other times it's a badge-engineered city runabout like the Aston Martin Cygnet.Back in 1998, BMW did a similar move and produced a car that was like nothing it had built before. Well, not since the 1950s anyway. This is the story of that car.All vehicle data was sourced from the relevant manufacturer. The BMW Z8 BMWThe 1990s were a good decade for BMW. Its 3, 5, and 7 Series sedans were class leaders across the board, and the introduction of the retro-styled Z3 sports car and X5 SUV expanded its offerings to a whole new audience. Among these mass-produced models, the BMW Z07 concept was revealed to a presumably stunned public in 1997 at the Tokyo Motor Show. The Z07 Intended to pay homage to the BMW 507 from the 1950s, it echoed many of its styling cues. Under the skin, the Z07 was thoroughly modern, with an aluminum chassis and body panels, and the running gear from the upcoming E39 M5. That meant a 395-hp 4.9-liter V8, a six-speed manual transmission, and a limited-slip differential managing all that shove to the rear wheels. Z8 Goes Into Production BMWWith very minor changes to the design, the Z07 became the Z8 two years later when it went into limited production. Pricing was ambitious, but not quite in the league of comparably powerful Aston Martins, Maseratis and Ferraris, and understandably so – this was the marque's first foray into the big leagues. The Z8 was promoted by BMW as an instant classic, despite that sort of thing being up to the customer to decide. BMW also snuck the Z8 into the 1999 James Bond movie, The World Is Not Enough, where it was promptly cut in half by a helicopter-mounted chainsaw. Sports Car or GT? BMWIt certainly looked like nothing else on the road, and while those retro-inspired lines could easily have looked like a caricature of some earlier model, the Z8 managed to pull it off. Contemporary road tests praised its performance, but claimed it was more of a grand tourer than an out-and-out sports car. BMW saw it as a primary competitor to the likes of the Ferrari 360 and Porsche 911 Turbo, with grand tourers like the Jaguar XKR convertible and Aston Martin DB7 Vantage of secondary importance. Build Numbers BMWAlmost three decades on, these market segmentations matter little, especially since enthusiasts who can afford a Z8 won't be pushing them to their limits at every opportunity anyway. The Z8 was in production for five years, and 5,703 cars in total were produced, making it relatively rare. Z8 Values Values over the past five years have risen steadily, peaking at $445,000 for a pristine 2002 example with just 5,000 miles on the clock. Higher-mileage cars with patchy service records can change hands for a little under $100,000, which shows that not every Z8 owner considered their purchase to be a future classic. That sentiment has certainly changed, though, and you'll need at least $200,000 for a good example these days. The Alpina Roadster V8 BMWBlogAlpina has had a long and close relationship with BMW for decades and it put this partnership to good use when it developed its own version of the Z8 called the Alpina Roadster V8. This model went into production after the Z8 was discontinued and featured some interesting changes that leaned into that grand touring alter ego that many claimed it had been hiding all along. Alpina Versus BMW BMWBlogInstead of the S62 engine that had powered the Z8, the Alpina Roadster had a modified 4.8-liter M62 engine that had already done duty in the Alpina E39 B10 V8 S. This engine was profiled for low-down torque instead of peak power, so was 25 hp down on the Z8, but it had 14 lb-ft more torque which gave it better flexibility. Out went the 6-speed manual to be replaced by a 5-speed automatic, and the suspension settings were made more compliant, too.The end result was a proper grand tourer, with oodles of torque from low down, and a more comfortable ride at cruising speeds. The Alpina Roadster V8 wasn't ultimately as quick as the Z8, but 0-62mph in 5.3 seconds was hardly sluggish. It was a lot rarer than the Z8, too, with only 555 units made, 450 of which ended up here in the US. Value Versus Price BMWBlogWhile it would seem foolish to take a purpose-designed sports car, remove its M-division engine, and turn it into a cruiser, the Z8 clearly suited its new role, and it seems to resonate with buyers, too, as the average price of a good Alpina Roadster V8 today is $297,346, almost 30% more than a comparable condition Z8. BMW Z8 Rivals FerrariBMW wanted to compare its new retro-roadster to cars like the Ferrari 360 Spider and Porsche 911 Turbo, but in reality, it was a closer match to the likes of the Aston Martin DB7 Volante, Mercedes-Benz SL600, and Jaguar XKR Convertible in driving feel.The Ferrari 360 Spider offered similar performance figures, but was a more focused performance car, leaving the grand touring duties to the bigger V12 Ferraris like the 456M GT and 550. The Aston Martin DB7 Vantage was a closer competitor to the Z8, producing similar power from its 5.9-liter V12; it was almost as quick, looked even more beautiful, and had the cache of its famous nameplate that buyers at this level valued. Close to 25 years on and the market has come to appreciate the retro BMW's charms, as DB7 values have been averaging $50,908 over the past five years compared to over $200,000 for the Z8.Bring A TrailerAnother rival, closer to home, was the Mercedes-Benz SL600, an aging roadster produced during Mercedes' golden period that still looked and drove superbly, even if it wasn't quite a match for the Z8's impressive straight-line abilities. Fitted with a torquey 6.0-liter V12 motor and an automatic transmission as standard, it was more at home as a grand tourer. It was priced within a few thousand dollars of the Z8 when new, but average values are now hovering around the $31,000 mark. A Modern Classic From New BMWThe Z8 was a quirky addition to BMW's straight-laced range in the 1990s, but beneath its retro-styled exterior was a very modern machine. It straddled the line between sports car and grand tourer, making it a difficult car to match up against contemporary rivals, but its charms have proven to be long-lasting, and this retro-modern creation with its iconic V8 is now well and truly a modern classic.Sources: BMW, BMW Z8 Forum, Ferrari, Mercedes-Benz, Alpina Automobiles, Aston Martin, Classic.com