I bought my car from a authorized roush dealer. yesterday when i went to get my hard tags, i was looking at a stage 3 roush. i asked my salesman was there any way to get the blower added to my car and be waranteed. He said yes, all i would have to do it talk to the regional roush manager to have it setup. he went on to tell me that the stage 3 was once just like my car and it can be done.
the down side is it has got to be VERY expensive, the good side is what you spend extra, you still have a factory warantee.
if i were in the market for a blower now, i would try to get hold of the roush regional manager in your area.