I made one out of an ebay T04S once. Worked awesome actually. The shaft on the stock turbo seems to be the standard size - or at least, not big. The backing plate and everything bolted straight up to the turbo. I did no balancing on the unit but it ran well for about 4 months @ 13-14psi.
Just check out the bolt pattern/spacing on the backing plate. As long as it will bolt up to the center section of the stock turbo, the other items should fit on.
Not super technical I know but its the only thing I went by?
it worked lol