A couple of thoughts.
First, keep in mind this is not a problem with the product, it's only a matter of having the caliper being wider than stock.
Secondly, much of this was done to fit the stock wheel more than aftermarket ones. If you can't fit the stockers then why make it?
Next, it MAY be possible to make the kit with more offset to move the rotor even more inboard. Not sure, been a long time since I checked other issues on this one.
Most 20" wheels should fit this brakes kit with ease unless it has some sort of multi piece design to it that places the bolt ring in the area of the caliper. This is where there are problems.
Lastly, if anyone wishes to send me a wheel to do test fit on I'm happy to help.
Todd