Everything is reversable, so mod away I say !
For my AC/DC machine I have -
1 x set mirror blades
1 x batch Leds -some, not all
3 x guitar mods from Pinball-Life
2 x drum mods from Pinball-Life
1 x set mirror lightning bolts
2 x red/black AC/DC stickers for the bell face mod
1 x set under playfield rails
1 x copper cannon mod from UK
And i will add the swinging bell mod sooner or later, and my own custom topper for the machine, and I plan on something major for the playfield as well very soon. Everything can be reversed, but i would leave it this way forever whether i sold it or not, cause the next person would love it the way it will be soon anyway.
Mod away Pete, any BNIB machine can benefit.