I'm assuming you're in the US and are looking at a manual tran.
3i sport has 15" steel wheels. 3i touring and 3s sport have 16" alloys. 3s touring and gt have 17" alloys snowflakes. You cannot get 16" alloys on a 3i sport from the factory, but the dealer will put the 16s on for you if you're willing to pay for it. This has always been the case. The 3i sport is stripped to the bone. 15" wheels, no air, power nothing. It is intended to let the 3 compete at price with the crappier low end subcompacts. IMHO, unless money is a serious issue or its exclusively for autocross, the cheapest you should go is a 3i touring with the ABS/SAB/SAC package. It's a much nicer car all around, and the safety package pays for itself via lower insurance rates, even if you aren't going to autocross.
The 07's are only slightly heavier, probably around 20lbs. I don't know the weight difference between the 3i sport and touring, but it's probably about the weight of the air conditioning. The i touring is 100 pounds lighter than the s sport (2.3l engine) and 125 lighter than the s touring (17" wheels and side sills).
3i sport has 15" steel wheels. 3i touring and 3s sport have 16" alloys. 3s touring and gt have 17" alloys snowflakes. You cannot get 16" alloys on a 3i sport from the factory, but the dealer will put the 16s on for you if you're willing to pay for it. This has always been the case. The 3i sport is stripped to the bone. 15" wheels, no air, power nothing. It is intended to let the 3 compete at price with the crappier low end subcompacts. IMHO, unless money is a serious issue or its exclusively for autocross, the cheapest you should go is a 3i touring with the ABS/SAB/SAC package. It's a much nicer car all around, and the safety package pays for itself via lower insurance rates, even if you aren't going to autocross.
The 07's are only slightly heavier, probably around 20lbs. I don't know the weight difference between the 3i sport and touring, but it's probably about the weight of the air conditioning. The i touring is 100 pounds lighter than the s sport (2.3l engine) and 125 lighter than the s touring (17" wheels and side sills).