I've now spoken with 2 techs at Corsa. They indicate the feedback from Caddy dealers (or authorized installers) when trying to install on the 08 -09's that the hangar brackets are different and need a modification to fit.
They (Corsa) have no intention of producing a new axle back system for 08-09 STS's. Said a good muffler shop can easily adapt it to fit.
I found a set of brand new Corsa's on the net for $550 NEW in the box! Has a bunch of them too. This company bought out Regency Conversions (a Caddy authorzied installer) that went out of business, and he is just trying to unload the inventory of exhaust systems.
Also - to set the record straight. The correct part number is 14157, NOT 14158. You will see ad's on the auction site stating both. The are completely different exhausts.
See this link--->
CLICK HERE and look at the drawings between the two systems. The STS uses the shorter pipe from exhaust take off and the short tips from muffler to end of the tips.
FYI.....
I'll let ya know on how difficult the mod is next week. Going to them them Monday and will attempt myself first (have welder and steel to fab something new if needed). If that fails, to the muff shop for more experienced hands.