You got me looking at the mr100 design (I used to have a mr1 to compare it to) and I like what they've done. Sorry to say that I don't think you'll find a better bolt or valve, and it looks like they changed the springs, so probably a spring kit is not going to be easy to find either. Trinity makes a aluminum clamping feedneck, that might be worth it if the stock one feels like it isn't going to last, I liked their mr1version for sure. You could also replace the Asa with any on/off one (doesnt have to be spyder specific) but really that's just another couple of orings to worry about. If you really want a reg, you could also look for a bottomline regulator, that would probably be easier than finding an inline adapter that fits and covers those holes that the grip use. But really, I have to agree that one of the neat things about the gun is its simplicity, so I vote feed neck and better paint to take care of the breaks
Oh and i'd suggest trying to borrow someone's apex barrel tip sometime, some people would count that as a must have woods ball upgrade depending on your style of play.