If i can remember correctly

A t3 is a standard 2wd turbo.
this at stage 1 is the same turbo fitted with a 360 deg bering.
stage 2 is then a bigger inlet housing and fan blades
a stage 3 is then a bigger exaust housing on top of that.
a t 34 is just a stage 3 turbo and thats just what they call it and thats the same as a t3 hybrid

a T4 however is the rs500 turbo which has the bigger inlet housing and a bigger still exaust housing

its been a while but i think thats about it, a hybrid T4 is the T4 with a 360 bering

the 360 bering allows you to run higher levels of boost.

hope that helps

although i might not be 100% correct?
someone may be able to clarify

the stage of the hybrid depends on what break you want to be able to run. not sure how that equates in to bar......

send these gys an e-mail. they are very helpfull and imo do the best turbos.

http://www.turbotechnics.com/docs/index.htm

thnks Paul