A simpler solution to the mvp firing pin is an ego/510 adapter. Down side is it won't look as pretty unless theres a beauty ring for that I've not seen but if function is your bigger concern its a good idea (imo). Its a super common issue with the mvp. Also I think you mentioned your coil was at 1.3 if memory serves thats a tad low for the mvp. If your v/w was cranked up too high it might have exceeded its amp limit.