how did you go about doing this? Ive wanted miata rims for some time but i wasnt sure if the centers bores would fit.
It's not something I could do myself. You'll need a very good mill and the proper fixtures.
I talked to a few people around here that have had custom wheel work done. They recommended a local shop that does wheel repair and custom wheels.
The place I used did an excellent job of keeping the c-bore centered on the wheel, keeping it round, no burrs, etc... all without damaging the wheels at all.
The downside was they charged me $30 per wheel ($120 for the set). But if you can find a set of wheels for under $400, even the added cost of the wheel shop, it's still much cheaper than buying a set of Volks at $250+ each wheel.
Strangely, I've stumbled upon an extra set of 99+ Miata wheels. I'm not sure if I'm going to bore them out, too or just sell them. I already have 1 set of Miata wheels custom fit, as well as 2 extra B14 SE-R wheels all for just race tires. I don't know if I need another set of 4 Miata wheels for more race tires (or maybe for the street).
-Larry MacLeod
'96 SE-R in ES (soon to be GS)