I got a response back from BPD. Just noticed this same thing when backing into his garage in bright sunlight. Very slight... Was surprised I e-mailed him on this just after he noticed it. He has been talking with others and from what he reported, it very well could be Turbo seals. There has been a bulletin on this, and BPD had both his replaced. Less back pressure could easily affect how well the seals work.
He did say that Darrelli has new bigger volume turbos in his SHO, which have much better HD seals and he has had no seal leaks in months of driving. Guess I need to call Darrelli... We talk every so often. Not sure if Darrelli has Livernois catted or catless down pipes. His car has been the one most of Livernois mods have been tested on. His radiator came from Torrie, and possibly the 3 bar MAP, as he got it early on, after I did.
Note- Flex radiator not an issue like the one on the SHO. The early years SHO seemed to have over-heating issues when driven hard,
requiring a larger radiator. I have made as many as 10 1/4 mi runs in one hour and have never had an issue. Also no smelly tranny like I can get with my G8, even though it has a second tranny cooler.