Update:
This weekend I changed my cheapo P-bass copy over to BEAD.
What I had to do...
1...trussrod: nothing
2...bridge: B-string would not fit through the feed hole in the back of the bridge (string too big)...I reamed out the hole with a small square file...5 minutes and it was fixed.
3...nut: the nut material is some strange plastic...not a rigid plastic like on my Yamha, rather a semi-flexible plastic...the string pressure alone was enough to widen the slots, except for the B-slot which I helped ever-so-slightly with a small round file (not a big job,,,took all of 2 minutes)
5...action: only had to adjust action on the B slightly...string is so fat that it felt a mile off the board, even though it wasn't...I lowered it quite a bit and surprisingly did not suffer undue string buzz.
6...intonation: B and E strings required a tweak (had to slide the saddles back), but the A and D strings were still quite good.
Playability...surprisingly good...B string (a 0.130 Nickel round-wound) is not floppy, Action is good, and bass feels fine...it was already setup well, so the changeover was really painless.
Sound...the B string ain't bad...I've played better, but on much better basses...I've played worse on much better basses, as well. As B-strings go, I give it between a 7 and 8...after a little post-installation tweaking, I hope to get it to an 8.5
By doing this, I've taken my first steps towards seeing whether or not, I really want (or need a 5 string). And the investment was minimal (about $7 for the string) , and mod completely reversible.
How's THAT?