500-550whp is typical in a p1, but give the motor forged internals, good heads, a boost camshaft, proper fueling and exhast with high boost from a p1 and 600+HP is there forsure.. if you want 700whp and such a d1 is better, or a f1 for that matter.. Plenty of people on ls1tech have shown 600whp+ using a p1sc.. I was one of them, and the guys at ls1 tech helped me out before I went forged.. but if you are shooting for those levels a d1 does make it easier..