The GS Brembo calipers will fit the non-HiPer Strut strut knuckles.
The real question is the value - is the additional pedal feel worth $2000? (The caliper assemblies [with pads] are $1,074.76 each - plus rotors, which are surprisingly inexpensive). Maybe used calipers will appear soon in the scrapyards?
You are probably better off trading in your Regal Turbo for a 'real' GS. As a bonus, you will get the sweet 14.5" flat-bottom low-inertia GS steering wheel for free!
You're absolutely right about the value of the GS upgrade from a (2012) Turbo 2 or Turbo 3 to a GS. It is worth it.
I'm actually not interested in the GS calipers because of the price (unless it drops significantly).
You can get 2010-2012 CTS-V 6 pot calipers which are pretty much the same as what MB uses on their bigger AMG models for about $500 each. So no sense in buying the GS calipers at that price. The 2006-2009 CTS-V calipers were about $170 each. When I got mine for another project that I didn't end up using them on, I thought they would be cheap Chinese knockoffs. What I got was real Brembo calipers, made in italy, looked real nice. But then again that is what was kinda expected as they were ordered with GM part numbers.
Good news of the GS discs are inexpensive, I still haven't seen the price on them anywhere. a DBA5000 style rotor would be nice with the aluminum center cap, they run at $1000 per pair, so that is a bit pricey but right now they don't have fitments for a regal.
It would be nice to know what parts bins they used to dig up the parts to get some sort of cross reference.
I guess what I'm getting at is that the mounting pattern and caliper off set looks like a GM standard, and if so it would open doors to a lot of options. The discs/rotors as well look close to being a low off set type, and the 5x120 bolt pattern and hub bore are identical to GM global dimensions which are on the Camaro, CTS-V, Vette, etc.
The only way I'll find out is pull the wheel off and try the 4-pot cts-v calipers. I have to see how it mounts, if it will mount and how it sits.
Since I don't have a GS, I don't know the GS disc/rotor size, offset etc, and while companies like raybestos do list the turbo's rotor info, they have no info available on the GS rotors. Can't find that anywhere.
