What a smaller port size will do is a multi fold issue.
The smaller port window and runner will increase the intake charge speed. (Velocity) This Leeds to a crisper throttle response. A ever so slighter leaned jetting, better fuel economy.
The draw back is a limitation on max power in the upper RPM range. The amount of HP loss is a wide and varied thing since your now comparing intake manifolds and engine builds.
If your out for maximum HP & TQ., the RPM-AG IS the best street, street/strip intake currently available and it should be ported to the max. Otherwise, you’ll be just fine with any reasonable intake up top in there as fast condition.
However! Far be it from me that I should dissuade you from going that route to maximize your build!
