A larger pump will create more outlet pressure and more inlet suction (duh). No matter the outlet potential, the regulator will modulate at "X".
Enlarging the inlet plumbing will minimize suction.
The S-Gator BRZ/GR86 tests evaluate inlet plumbing/baffling and it is not encouraging.
The you-tube video I watched justified a bigger pump because they opened-up bearing clearances. I do not get that (loose) objective, and they had no follow-up results.
jim