The std pump is certainly fine at 380bhp, the 941, but as said a simple job to rewire and just use your existing feed to trigger the relay.
Up behind the rear seat upright on the left hand side of the car there is a convenient 8mm hole that I used to hold my fuel pump relay holder, also easy to take out then at shows etc for a bit of extra security.
Also make sure you put on a new earth, direct to battery, don't go to body as the whole point is to try and eliminate as many high resistance points as possible, so direct is best, 28/030 cable would be ok.
Talking of rewires don't forget the fan as well as these are hopeless on cossies.
tabetha