The sporadic electrical problem sounds kinda like the fuse box issue. There are posts here about it.
Good luck, that's sounds frustrating
Jet black e92 6mt 335xi:
18" BBS RGRs, KW v1, ESS Stage 2 flash, VRSF 7" FMIC, VRSF downpipes, JG Mods m-tech front, mtec V3 AEs, BMS OCC, hardwired valentine 1, p3cars gauge, amber delete, sport seats, factory oil cooler.