Good morning I have an 05 6spd, recently put a gutted converter on my car I knew there would be the cel on but I scan it regularly to be safe. Any how I'm throwing a rear 02 sensor heat code. Did I ruin my sensor. Also after redlining 1st I get hesitation at 8k rpms in second and a large plume of thick grey smoke is that normal? Any knowledge or experience with this would be greatly appreciated.