It's a fairly simple process, at least based on my 5er it would be.
When you do this, you'll need to change out your spindles, hubs, and brakes.
If there is a 5 lug car that has the same spindles you'll have to do even less work.
The first step would be to cross reference your wheel bearings, and see if it comes back with a hit on a model that has 5 lug wheels. If it does, buy that cars parts from the bearings out and you're all set.
If there isn't one that easy, you're best of finding a conversion kit, or someone who's done it already.
2002 BMW 530i
1997 Ford Mustang GT
1995 Honda VFR 750 (For Sale)
1964.5 Ford Mustang