Hey, the 2871 is the disco patato thing is it not? Would work very well on a ej20! But something you need to consider is the amount of fab work that is going to be involved. You could go for a p20 vf34 and get nearly the same results, with the added ease of having off the shelf headers and up pipes and shite to suit.
Should all work very nicely with the auto, and feel pretty damn strong on the street.
Oh, and is the avo400 thing just a rebranded and more expensive 2871??
edit: re read your post, 2860 is the spud. Been a long time since I played silly buggers with cars, but just getting back into now.