I got the mudbucker installed yesterday. The only mod to the body was to make the cavity just a little bigger. This was done on the bridge side of the whole. I'm liking the tone I'm getting now. I played it last night for about a half an hour. I've also put a mudbucker on my P-bass. One pickup and ...
Whether I bring the 4003, the Fenders or the Gibson, my Rumble 100 sounds killer; at home, at rehearsal & at small trio gigs.
It's really light-weight and inexpensive as well.
LOVE that little tone box!