can you spray on a T-rex
#2
Yes, you can spray with a T-Rex. Some people say it bleeds off, but the numbers I've seen at the track and the dyno do not indicate that. It would also depend on how much you plan on spraying. Anything under 200 should be just fine.
#4
Then do it, I think you'll be pleased with your numbers. As far as a converter goes, I'm not really sure. I'm very set on running a 4200 with nitrous, but I haven't actually done it yet, so I won't try and point you in any direction on that. I think that 4000 with a 2.2 str would work out, as long as you have high shift points (you should anyways if you're running a TRex). It's also a matter of preference, but usually the people who are going with a T-Rex like it more on the extreme side.