Well, my first Mini owner experience was not very good. When I picked up my winter wheels I bought off ebay, I was informed, "I hope they fit". I drove 100 miles in my 2008 clubman, met another clubman owner who then informed me of the lug size change.......needless to say if anyone wants a set of flicka 16"" wheels with killer near new m&s tires for $4oo.oo I have a set....just be sure your car is pre July 2006 build date.....as Groucho Marx always said, "any club that would have me as a member I wouldnt want to belong to"
Welcome, thanks for joining Motoring Alliance. Unless one was really keeping up with MINI stuff the lug size change would not really be noticed at all. You do have options. A machine shop can enlarge the holes, it's not much, just 2 mm. Alternatively, you can get studs that adapt the 14mm bolt to a 12mm bolt. They are safe, I've been running a set since 2007 on my late 2006 MINI. Lots of track days, lots of wheel swaps with no problems.
Have you tried a test fit? If so having a machine shop open the holes will save you a headache. Going studly would also work. Welcome to M/A Austin.