My coworker owns a 2001 Audi S4 (twin-turbo V6, 6spd manual) and we were going over some of the mods available for his car. One really jumped out at me and it seemed such a great idea for any F.I. vehicle. A boost gauge built into the tachometer:

http://www.stratmosphere.com/oct_s4_boostgauge.htm

Convert it to PSI instead of BAR. Might be a nice custom job that someone here could whip up

 

thats a pretty cool design. however i doubt anyone would want to spend that money on custom fabbing something like that for our trucks. if the production model costs 400, i would imagine it would cost at least 1000 to make a whole new one for our trucks. its still pretty cool though