It depends on the approach. Technically/legally, your entire factory drive train warranty would be voided by Ford after installing the Roush blower.
But that is the technicalities of who's warranty covers what parts once installing warrantied performance parts by an authorized dealer.
1998 Roush: M112'd Aluminum block 4.6L 2V 6 speed track car
1999 SVT: Mostly stockish
1970 Mach 1: Resto-modded monster
2000 Roush #5004 - World's FIRST M112'd V6 Mustang. Sold, but not forgotten.