Here is Florida, I chuck the P3 plug. Its too hot, and overheats the engine. We used it for break-in in only. I used RB 5 & 6 Turbo plugs and the car had stable 234 F temp and great power. The 6 seemed better than 5, but its getting cooler so we might switch to a five now depending on the temperature. I believe an O.S. P6 & P7 should be good also.