The OEM applications tend to have 1-piece rotors, rather than floating rotors. And they tend to be smaller than the aftermarket alternatives. They are almost never less expensive to add on to the "lesser" models than an aftermarket big brake kit, unless you are lucky enough to find a wrecked car and buy the parts used. For example, the 1-piece rotors for the Nissan 350Z Track Model are about $500 EACH at your local Nissan parts counter!
There are rare exceptions to this. In 1993, Ford introduced the Mustang Cobra R, which came with much better 4-wheel disc brakes than the regular Fox chassis Mustangs with rear drum brakes. A few years later, Ford Motorsports offered a brake upgrade kit called the M2300K for just $1200, which included 13" front rotors and 2-piston PBR calipers, new SN95 steering knuckles and hub assemblies, a new master cylinder, bigger brake booster, new rear axels, rear disc brake conversion, parking brake cable, and tons more stuff. I've never seen so much hardware (and so badly packed!) for so little money.
When I was at the SEMA show in Las Vegas, I spoke with a Chrysler engineer in Mopar Alley, right next to the SRT-8 on display. He told me the SRT-8 uses different knuckles than the normal 300C. That probably means two things:
- The StopTech and Brembo big brake kits for the 300C will not fit the SRT-8
- The SRT-8 brakes will not fit the 300C
There's always a chance they will fit. But it's not a sure thing. I'll be investigating this when I get my hands on an SRT-8 and will let you know what I discover.