Well, I don't know how fast you want to go, but that turbo is going to require some major tranny and fuel system mods for it to work.  Really, the biggest I would go with for a street driven TGP is a GT2871R, which IIRC supports 400hp.  But for most everyone on here, the GT28RS is plenty big enough.  It should provide a very large gain.  

Shawn

is the turbo i was looking at and the two that you named...are they all direct bolt-in replacements??

oh yeah i know that those bigger turbo require alot of mods and supporting tuning to run properly...i was really just wondering if the characteristics of that turbo (gt30 71R-WG), could ever complement/work with our displacement and rmp range in a moddified engine (higher flowing heads, exhaust, bigger injectors, fuel pump and all the supporting tuning)

basically if we had a need to reach 450hp would this turbo (compressor map and turbine map, couldn't find any) be a good choice....or are their other bigger turbos that would work better.

i sent atp an email and they refered me to maps of the GT3071R becuase they don't have any for the GT3071R-WG...so the guy said they are very similar (compressors have the same wheel size and trim, A/R is the same too) here are the links...could somebody with better knowledge of reading the maps explain why this turbo would or would not be a good choice for a high hp build up.  

trubine: http://www.atpturbo.com/root/maps/gt3071rturbine.htm

compressor: http://www.atpturbo.com/root/maps/gt3071r.htm

the guy who emailed me back said "this would be a 'sweet' set up."  jee whiz thanks for nothing...