It's a pretty good setup, some would argue the "best" setup for a canned tuner. I had it on my LMM, defuels were not bad at all, especially compared to the Quad I had before. I didn't have any issues in the 2 years I had it. I use it now for just gauges and run EFIlive tunes from Duramaxtuner. Don't think you will be disappointed. ChrisIf anyone knows anything about this system good or bad let me know. And Does anyone know if this system defuels when shifting?