I'm talking exterior wise...Besides the grill, headlights, taillights, and wheels, what else needs to be changed? Thanks.

paint the moldings, bumper.

why neccesarily a 530? you just want the 2001+ style right? If that is the case then you listed everything above, if you want a 530 then buy a 530i badge, and paint the moldings to match the color of your car. Dont forget to change your front bumper to the 2001+ style. The bumper with round fog lights instead of the 1997-2000 squareish ones.