ur car now is 318 manual, rite ???? I think tis is d best for u to maintain d car power .......
Convert ur 318 to auto will cause u car bcome underpower.........if u want to drive auto , sell ur 318 and get 328 auto instead ......
+/- function ???????? As many said ....depend how deep is ur pocket ......nothing is impossible .................
but for me .......my advice is sell ur E36 and get e46 instead which got d function tat u want cos then cost u going to spend for those kind of conversion might be end up wit an E46 ..........
gud luck .........