Nitrous. Like I said, it's a low dollar set up, just well thought out. He originally had a 50 shot dry kit, and went mid 12's. Now it's a 100 shot wet/dry (don't ask, some weird science I came up with over dinner and drinks one night that actually worked great ) So honestly, it's not that much for the times he's running. Still a stock cam and internals. When we were towing it down for track day he kept saying if it falls off the dolly, just keep going and I was like, we got to go back and get the nitrous kit He said if he blows it up, he'll just call starkey road and get another motor