Is the T3/T04E really necessary to make approx 225 wheel HP or can I get by with something smaller? I'm not after max HP, but rather as much under the curve as possible. I'd like to start boosting at 2500, and have max boost by 5000 with no drop off up to 8500. Can I change the compressor or turbine wheels to better tailor the response and HP to what I'm looking for?

 

get a slightly smaller exhaust housing, that will give you faster boost response and probably a more torquey feeling. it will hinder top end though.

 

or just get a stage 1 turbine wheel