No way would I go with a T4 tubo as big as echocycles straight drag bike.
something a little more street wise but still arm tearing.
t3 turbo with garret core.
to4e 51mm inducer comp wheel
.5 a/r comp housing
stage 3 56mm exhaust wheel
.64 a/r exhaust housing.
Nice starter you can play with the trim of both side's of the Turbo on a 1800 - 2500cc engine you would expect an easy 200 -220 hp at 7lb's boost, fab up some spagetti headers, intercooler and plenum and your good to go.....
The Boost Is Good turbo Jethro mentioned is the only Rocket specific turbo kit available that I know of. All the others are special built. Your only other complete kit option is TTS Performance's supercharger kit. More knarly looking, more power, but also more installation costs. Check out this thread of stuff on the supercharger: