A wideband o2 gauge is a good idea for basically any car that will be modded any.
http://www.aemelectronics.com/wideba...fuel-gauge-25/

an Aeroforce Interceptor is a scan gauge that can read almost every parameter in the ECM.
http://aeroforcetech.com/products_interceptor.html

Boost guages are neato. Take your pick of what brand.

I personally like to have an oil pressure gauge, but it's entirely up to you as to what gauges you'd want.