I have been losing air in my tires for a few days. I spent 2 hours looking for a nail and there was none! i finally broke down and took it to a rim shop. It is better to go to a rim shop because they wont scratch your wheels like an ordinary tire shop would. So after trying 4 different shops today i finally get to a good one. The dude took my tire off and placed it in giant bucket of water after filling the tire to 42 psi. The leak was on the valve stem. The tps system was what was leaking. he tightened that bolt up and put it back on my car no scratches at all. Please check this if your tires are losing pressure before spending money at a tire shop! it would only lose air at night when the ambient temperature and the pressure would go down. This process was only 15 bucks at the rim shop but i gave the guy an extra 5 to torque to spec and no scratches and for working on a sunday july 4th weekend. The 4 tires shops I went to prior didnt want to touch it because of the TPS system and the low profile 18s. But the the point to the 4 shops is that if they just thought about it for a quick second they would have been able to fix it without remounting and balancing. i told them tps and only 2000 miles on the tires and i couldnt find a nail. if you are at a smart shop you would know first to check the tps connection to the rim/valve stem area.

hope this possibly helps someone else out.

Also i noticed a few things when the tire was off. first thing is that the frame has drilled out holes to make it lighter without sacrificing rigidity. also the exhaust has sound deadening material or a heat shield or both on the top part of it. pretty cool stuff