HO 900 getting beat by stock 900

Hey guys got a question. My RZR has the Stage 2 Polaris kit in it along with an SLP clutch kit and I can’t beat my buddies bone stock 900 XP. He beats me every time by a length and a half. No idea why. I’m running the clutch set up recommended by SLP and he gets the jump on me every time. Is it possible the clutching is that far off? Or do I have something else going on? Could the throttle cable need adjusting?