I noticed on my friend's `05 6MT Coupe that he has those little valve stem caps that turn red on the tips when that particualr tire drops below the set air-pressure.

Anyway, my mom has an 05 Coupe w/ Auto trans, but it has the sport suspension and tire package with the tire-pressure sensor feature. Recently her tire-pressure sensor gauge lit up on the dashboard. I noticed she has basic chrome valave stem caps, not the ones with the color changing tips. Her car was a showroom display model with black 20'' wheels which she did not buy, so they but the factory 19's back on for her. I think when they put the 19's back on they neglected to put the color changing caps on.

Are these an option? Do they only come on 6mt's? Do they play a crucial role in the tire pressure system? I am going to the dealer tomorrow with the car to fix a radio button malfunction, and I am going to try to get them to give me the caps.

Thanks.

- Jason