Wilwood conversion problem

I may end up leaving the SBP on the rear, but the problem for me with that is I'd like to sell my current wheels in a set of 4, in which case I'll have to go to the BBP on the rear now. The options 72bluNblu suggested seem like a less expenisve alternative to upgrading rears to discs. If I go with a spacer it will definitely be billet.