rickycrx

Bryan actually has some pretty good ideas there... An A/F gauge is only really useful if you are doing some tuning on your car, and is really only significantly important if you are running forced induction and want to keep a closer eye on what's going on with your engine (and even then, an EGT gauge is probably a better one to have)... However, if you don't know what you're looking for, the A/F and EGT won't help you any.

Water temp would be one that's better than our crappy little 'three bars' that give us a general idea of when the engine is up to operating temp, but even more important (and the reason why you should have BOTH) would be the oil temperature gauge. That way you can make sure not to rip on your car too much until the oil is up to normal operating temperature (~205 degrees, if I remember right).

I'd never buy a gauge to 'look cool' though... That would be a waste of time, money, and effort. About as effective as the silver 'nos bottle' fire extinguisher on the passenger side A-pillar of your favorite ricemobile.

Ricky