How much hp can a gsl-se fuel pump handle. I plan on street porting, a s4 intake swap and afc piggy back.

I don't have any numbers to give you, but I'm pretty sure that with those mods you're going to want more fuel. Better safe than sorry.

No matter what pump you run, be sure it gets plenty of power - by now your stock wiring has suffered some oxidation and will hinder the operation of any pump. Run a fused 12 wg wire from the battery to a relay to the pump. The original fuel pump wire operates the relay. Don't use the harness ground wire either - run a wire to a chassis bolt, or straight back to the battery.