Go to a wrecker and cut out the part of the loom you need and go from there. Stagger the joints and shrink sleeve them. Should look original if you are any good. BTW I understood the 'Cheap' reply was refering to the job price not the poster.
Good - Fast - Cheap: Pick any two.
E23 735i; E30 318i; E32 735iL (X 2 - 1 White and 1 Light Blue); E34 535i; E38 735iL; R50 Cooper; R55 Cooper Clubman.
E21 318i; E32 735iL; E34 535i; E38 730iL; E53 4.4i