Lotus V8: Sure, it's got less power, but make up for that with wonderful handling and a more neutral weight balance. A few modifications to the Turbos and you've got a viper killer.
Ferrari 355: Performance between the two is comparable, but I take the Ferrari for a few Reasons...
1. Style. To me, it blows the Lotus away (and with a car as gorgeous as the Lotus, that's hard to do!)
2. That sweet, sweet distinctive ferrari sound. Nobody does rip and snort like Ferrari
3. NA. The Lotus has a TT setup, and still doesn't manage the hp/L that the 355 does. Doesn't matter in overall performance, of course not. But it does add to my satisfaction.
Ferrari F50: This isn't even a debate, in my opinion. The comparison is between a street legal F1 car and a high performance Street car. The straight line performance is near identical, but once you factor turns into the equation, the Ferrari blows it away. A gut-wrenching lateral acceleration and a much higher redline are enough to do it for me. The Ferrari's superb aerodynamics aid in my choice as well. The only downfalls are that enormouns price tag and that high compression....a speed bump in Turbo application.
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"Ferrari isn't a car, it's a lifestyle"
-Enzo Ferrari.