Once you are running below fuel cut level, your stock fueling system will cope just fine as far as fuel pressure, injector duty cycles are concerned because the ecu can recognize and compensate for such boost levels. If you were going above fuel cut (12.5+psi) you would then have to have devices fitted to allow that boost level and also compensate with increased fueling. Since you are not going above fuel cut, the only thing you should be worried about is your manifold. If you are still using a stock unit, increasing the boost pressure will increase the stress on the #2 and #3 pistons because of the heat build up caused by the restriction in the runners. If you don't have one already, it's always best to change the manifold to one without the restrictions when increasing your boost levels.
