Sorry I have been reading through this thread and I have come in late.
R32's (RB20DET's) can run more boost standard than the R33. From talking to others it seems that the R32 can run about 12-13psi standard to the 10-11 standard for the R33. I believe the R32 has slightly lower compression to facilitate this.
As for getting an aftermarket wastegate, this is only really nessicary on big turbos which don't have an internal one. I have heard about people welding closed the interal wastegate and using and external, but to do this you need a new exhaust manifold and generally big dollars.
Anyway that's my 2c worth.
Jeff.