nitrous press gauge
I'd suggest getting the dynotune digital nitrous gauge. I've got one and love it. As far as fuel pressure goes, you could also go with a dynotune one. I prefer the sweep type gauge for fuel pressure, so I went with a Autometer gauge. And you'll want an electric one, not a mechanical one.
Go electrical. Hook up is much simpler and you really don't want a mechanical FP gauge in the car. They are worth the extra $$$. I like my full sweep Autometer Phantom series gauges. The Autometer Cobalt series is really cool too, I wish they where out when I had bought mine. 
Trending Topics
Get they DynoTune digital Gauges. They are really nice. I have their n20 gauge and a/f gauge(came with the a/f switch but will be replacing it soon0its nice though) and they are quality pieces. Here is my setup!
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
i like my dyno tune Gauges a lot here are a few pics at links
http://webpages.charter.net/silverz98/DSC00534.JPG
http://webpages.charter.net/silverz98/DSC00540.JPG
http://webpages.charter.net/silverz98/DSC00534.JPG
http://webpages.charter.net/silverz98/DSC00540.JPG