The Performance Handling package, RPO code PCZ, became available in 2008 for V-8-equipped rear-wheel and all-wheel-drive models and V-6-equipped rear-drive models. This package includes 7 spoke 18 x 8.5-inch 6 lug aluminum alloys, chrome optional, fitted with new P255/45R18 Michelin Pilot Sport summer-only tires.... STS V uses 10 spoke 18 x 8.5-inch front and 19 x 9.5-inch 6 lug aluminum alloys. Fitted with P255/45R18 front, and P275/40R19 rear, Extended Mobility – Pirelli tires.
Also includes Four-piston caliper Brembo brakes, RPO code J56, with front rotors measuring 355 mm x 32 mm and 365 mm x 28 mm rear rotors to provide enhanced stopping ability. All four rotors are vented.... Same as the STS V.
StabiliTrak with active front steering...active front steering available only on V-8 AWD.
Aluminum Strut Tower brace, V-8 and V-6 STS specific.
Stabilizer bars, hollow 33-mm diameter fronts, hollow 24-mm diameter rears on AWD and hollow 19-mm diameter rears on RWD. The hollow 36-mm diameter fronts are STS V specific but will mount on the V-8 STS.
And like I stated above, those are the 7 spoke 18" wheels that were also used on the CTS V....Anything else you want to be schooled on?
I wonder if this is similar to Ford. They started installing the 6.0L diesel disaster toward the later part of the 2003 model year. It may not have been available for all of 2007, perhaps only later builds?