tuner for 00 mustang gt

What size shot? If it's a small shot, you should be fine with a mail-order (email) tune. If it's a larger shot, you need a dyno tune.

SCT and Diablo are 2 of the biggest brands. But it depends on what your local tuner uses. Get his brand so you can be compatible when you get a dyno tune.

I don't know. I'm not familiar with the ins and outs of nitrous and dyno tunes. I would say you need a dyno-tune just to be on the safe side. Hopefully someone with more knowledge will come in and help you out.

But either way, check with your local tuner shop and see which tuner would be best for you.