It all depends on how much boost you want to run. Yes, a Type-R motor will handle 8 psi for a relatively reasonable amount of time. But if you really want to crank up the boost the high compression ratio of that motor is going to cause way too much detonation to be practical without race gas, retarded ignition timing, colder plugs, a rich mixture or any other combination of that crap.

How much does a typical Type-R swap cost? Like $4500 or more? With that kind of money you could take an LS motor and build it up to make more off-boost power than the Type-R motor (and since off-boost is at low RPM a VTEC motor wouldn't even really shine in this department) and take a helluva lot more of a beating than the Type-R motor, plus have enough money to put a limited slip diff in the tranny.

Back to the original question, T3/T4 is just a general classification of the housing size. It says nothing about how much the turbo is going to flow and at what level of efficiency. If you have a particular motor and power level in mind you can go from there to figure out how much boost and what kind trim of turbo to run.