Very nice work Adam.
Rebuilding the Pop Bumpers with new parts makes the game play much better - and it looks much better. There is a fair amount of time involved in the process, but it is worth the effort.
Yes, the pop bumpers are a bit of a pain to do while the playfield is still in the machine but very much worth the effort. Before hand I generally wouldn't get past the 25k jet level. Now with them rebuilt I regularly get to the 100k jet level and sometimes the 500k level.
Looks great. I see the ball gate wire forms look like new. Are they new or what method did you use to clean them?
For the ball gates and the wire forms I clean them up with some scotch bride and then buff them with a buffing wheel on the bench grinder. Same goes for most metal parts and if something is a little more difficult to get into I'll use the Dremil to get into the hard to reach spots. After buffing I give the parts a wipe over with a bit of windex on a micro fibre cloth and then wipe off any excess residue with a clean dry micro fibre cloth. Not much to it really, just a bit of time and patience.