Remember that levels 6 through 9 are for drag racing so the exhaust temps won't be around that long anyway. I've only gotten it up to 4/4 and at that level it touched 1100 for a short time and then dropped slightly. It's real impressive there, (s/b about 80 HP and 160ft lbs) pulls HARD with very little smoke. I do have a Bully dog intake setup for whatever it's worth. Still have stock exhaust. No codes (yet?).