with my mods do I need one? Wouldnt I want to but an Air/Fuel guage to tune it also?

 

It's a good mod. You can either go the JPrevost route and make the stock one adjustable (there's a tech article on the site) or buy one...GM has one for our cars, it's like $41 from the dealer. Can't remember the part number though.

It's a great mod, not only can you give your car some more pep, you can adjust it for all your other modifications.

 

Unless you plan on doing a bunch of street car custom eprom tuning then the air/fuel gauge is just a toy. It's a few LEDs that flash that really aren't accurate.
As for doing the AFPR...YES YES YES how many times must I say it before people understand that speed density EFI needs to be tuned with fuel pressure at the very LEAST!!!!!
You give your engine more air and let it starve with no fuel. How the heck do you expect to go faster with less fuel? If you've found a new way then please share the wealth but from where I'm coming from you need to adjust fuel pressure to adjust for the incoming air.
If you want to spend your money best to make the car fastest do the following: Do the AFPR for the cost of gaskets ($15) and then take it to the track and run consistant 60' times and look at your ending mph. The best fuel pressure will be the fastest mph NOT your best time.
If you want to do the AFPR then click on my name in my sig. Go to cars, then my car, then click on the link to the tech article that was made by Vader. It's got pictures and the whole she-bang.

 

Like J said. Its a must with ur mods. You will notice a big difference. And adjust it the way J pointed out. Good luck and come back when u get done and tell us how things worked out.