After reading and re-reading everyone’s experience and advice on exhaust options, and resulting sound files, I decided to go with the Corsa 14157 axle-back system for my 2008 Cadillac STS-V.
Just ordered the part today, so not installed yet on the V.
I had a Corsa cat-back system for my 2005 Cadillac CTS and enjoyed the system & sound, and I think it makes a nice match for the STS-V.
I was sorely tempted to follow my plan as stated, to replace the individual components with the Magnaflow exhaust & cross-flow muffler for the resonator, but the cost with shop support for dyno, adjustments, and testing as a project was similar to getting the Corsa axle-back system. I will still need to establish a clean before/after test regimen for the exhaust install.
Corsa offers this flow-bench testing to show that the 14157 system out-performs the factory exhaust.
The Corsa 14157 is not advertised to fit the 08 Cadillac STS-V, but rather the 05-07 STS. There were changes made by Cadillac in 08 for exhaust hanger location, so the system will need some adjustments at the muffler shop during installation.