[Nate2046]

Thats a good question. The one thing I noticed looking up the specs of the cars you mentioned is that the S2000 has almost the exact same overall dimensions as the Z4M but is about 4" shorter in wheelbase. If you consider that the main 'structure' of a car is between the wheels that 4" could account for a lot of weight. The overhangs beyond the wheels at either end are much lighter per inch. Of course the Vette has 10" more wheelbase and weighs less so theres obviously more to it than just that. I would guess that the more 'gadgets' (nav, elaborate stereo, additional airbags) coupled with the more luxury feel (additional sound damping, thicker, heavier, high quality materials) adds up to the difference between the two. Along with the heavier engine the Z4 also has dual exhausts with 4 heavy cats. The Z4M also has 18" wheels and tires vs 17" on the Honda. The rear hatch on the Z4MC also has that big heavy piece of glass. Lots of little things that add up.

Just as a reference for anybody else who wants to chime in these are the stats I got from edmunds.com. These were all from 2007 models except the 370z which was 2009.

Z4MC
3230 lbs 162" long 70" wide 98.3" wheelbase

S2000
2855 lbs 162" long 69" wide 94.5" wheelbase

Corvette
3179 lbs 174" long 72" wide 105" wheelbase

370Z
3278 lbs 167" long 72" wide 100" wheelbase