Do you have a means of checking you're A/F ratio? Sometimes a stutter or buck could be the car running VERY lean. I'm not sure of your setup, so I don't know.
Yes, you could raise fuel pressure, however, the car won't properly compensate at idle, and the car will run rich. RRFPR's can raise pressure as revs increase (vacuum decreases) and Cartech does make such a thing, so idle will not be affected.