i know that it is tough man, but the thing is it seems like the problems are endless. even if you do everything perfect, you are gunna have problems for a while until things have been replaced. i see it a lot where people do a top end rebuild and there coil goes and they wanna sell their blaster, it happens, but you just gotta push through to the sunny side
unless i missed anything............
a "big" problem would be something like a rod flying through the motor, piston coming apart and completely destroying a jug, or other major, expensive part breakage.
electrical problems really suck, but with a few cheap tools and a little patience there's nothing on one of these blasters that can't be handled in an afternoon
C. properly maintain and tune, modifiying as needed and enjoy it.