Mine is a mostly stock 3.2; as you said, perhaps a little smaller diameter would be better.
I haven't installed them yet!
So far I am impressed with the build quality. The flanges are thick. The welds look good - not gorgeous, but plenty good. I had to sand off a bit of casting residue and use a grinder on some spots, but nothing major. I hope to install them tomorrow and will report on how they fit.