I have no exp. first hand - im a textbook expert (forums are my textbook) but I would go with the rb25 turbo, as I would have thought it would have been less laggy, because I have read in threads of ppl with rb25's upgrading the turbo for a vg30 item to make more power. IIRC they are making 220-230rwkw's on rb25's with the vg30 turbos, where as your rb25 turbo will max out at 180 - 200rwkw.
Sumo