What do you mean, bad handling? In MW, maybe, but in real life it'd stomp an R34 with a big, heavy body-kit like the one Eddie's car has in UG. In real life, though, I'd take the R34, just because it'd turn more heads and it's twin-turbocharged.
Since Eddie's car is never available in any NFSes that the BMW is in (without hacks, vinyl mods, or the MW Mod Loader, that is), and the handling of UG/UG2 and MW/C aren't even close to comparable, the entire question is pretty much moot. It would be awesome to see Eddie Vs Rachel Vs Razor Vs Darius Vs Ryo Vs Cross or something, though.