1) 10 mm spacer
2) Drill and tap hubs for 4X114.3 bolt pattern
3) Only if the center hole is 57.1 mm or larger.
Add cost of wheel bearings necessary to R&I hubs for drilling.
Cheaper to get OEM 14X6 weaves and put a BBS sticker on the center cap or get the 15's for an E30 in 4X100.