Originally Posted by akhbhaat
Why are you using 3483 lbs for the M3? According to the thread at the top of this board, the car weighs in at 1655 kg (3648 lbs, EU4). If you've subtracted driver weight from the M3's number, you have to do the same for the Porsche cars (which also use EU4 spec; Porsche actually lists weights in both EU and DIN on their site). The GT3 is only 1395 kg/3076 lbs by the standard definition of "curb weight."
Also keep in mind that the RR P-cars have much better traction off the line than any FR, including the M3. The M3's ET will be much closer to the Carrera S (though it'll trap faster) than the GT3, despite the power/weight ratios.
I took traction into account with my 0-60 and 1/4 mile times.
For the GT3 I was using the actual weighed curb weight by Motor Trend (NOT test weight). This includes base curb weight plus whatever options that particular GT3 came with. I am sure that the M3 the car mags get ahold of will weight somewhat more than 3483, since it will undoubtedly have some options.
I am, honestly, surprised that Porsche lists the GT3 Curb weight at 3075 lbs on their USA web site. Both Car and Driver and Motor trend have it at 3235-3045 in their recent articles. Perhaps Porsche's definition of "Curb weight" is different than the norm (i.e. no liquids at all). 160--170 lbs is a BIG difference.
Example 2: The Cayman S Curb weight is listed at 2954 lbs for manual transmission. Road and Track Aug 06 has their Cayman S curb weight at 3130 lbs! Another 176 lb "error?" I think Porsche grossly underestimates their curb weights for marketing purposes.
For reference, the BMW 335i Sedan curb weight is listed at 3591 lbs and C&D test car curbed at 3635, so only 44 lbs off. This could be accounted for by the heavier 18" wheels of the sport package and extra power in the seats alone.
So with normal stuff on it the M3 will probably weight about 3525 lbs, or 300 lbs more than a GT3 -- not bad!