3 piece wheels are bolted together, not welded. And you can just use an assortment combo of different width inners and outer halves to create the back spacing and width you want.

Of course you are still somewhat limited in that..I like 2 piece wheels since you can pretty much put the center any where you want in the outer to get the exact back spacing you want (As I did on my car, and we do with wheels we build in Oz all the time)

I've never used stuff by VWW though..I buy my centers that are made locally and outers from another company.