what are you using the car for, drifts, burnouts, circuit etc? What is your max rpm? limiter bashing? I believe the power curve ramp up is where some of the dramas are, as in a sudden vertical power graph (ie: gaining 200kw in under 1000rpm) can cause problems wth the oil pumps, but so long as everything is within tolerance, balanced correctly & your using a good balancer (ATI or ROSS & done up properly), with a quality oil pump, i cant see you having too many issues really, considering what other have done with rb30's! You could even use a block girdle to further reinforce it further (platinum racing offers these)! The problem with the oil pumps is common to all rb's really! Not sure how you managed to spin a balancer if it was done up right?
Darren is a very competant engine builder & is helping me with my rb30/25, we've discussed alot of these issues, it just seems strange that hes talking you out of the 30.