I have a 2010 R/T Classic and am looking to upgrade to Brembo Calipers with larger rotors. I wanted to know if 4 piston Scat Pak calipers are a bolt on replacement. I hear Hellcat 6 pistons are not, they require a spindle change. But, will the 4 piston Brembos on Scat Paks interchange? What about the older SRTs that had the 4 piston Brembos, like the same year as my car, but had the 6.1L instead of the 5.7L? Are those Brembos any different that the current Scat Paks? Would they be a bolt on replacement for my car? I would be surprised if they were doing spindle changes for the 6.1L SRT cars back in 2010. Any help appreciated.