I just tried my Tornado on my Max it is much quieter than the stock coil and is dead on with the VDI's not wandering all over. I also changed batteries from the ones that came with the Max. I don't know if the batteries are at fault for all of the other variables that seemed off before, only time will tell. Anyway I am running the Tornado at zero,0 threshold 6 bars of sensitivity iron discrimination maxed and this is the best performance I've got so far. Maybe a fluke but I'm going to stick with this coil for awhile.