I'd LOOOOOVE to get this TPMS from Stack, to know when my tire temps are optimal for traction at the track and when doing standing starts. But if you thought the original gauges were expensive, check out the punch in the balls on this one
http://thmotorsports.com/stack/stack.../i-394774.aspx
Once I re-design the audio system, I'd like to get a gauge pod in place of the navigation screen
I'm also toying with the idea of setting up a heating element next to the rear tires so they warm up while I'm driving around. Something around 400 watts on each side. Kinda silly, but I like to think outside the box.