Decisions decisons...if you'll be happy with 300whp or so, go 20G, the price is right and it's a good setup. If you want more, then go for the FP3065 or, like I suggested above, contact FP about doing a bolt-on HTA3076.
Here's one on a pretty tricked out evo. If you got anywhere near the numbers this put down, you would be in good shape
http://forums.evolutionm.net/showthread.php?t=332881