If you go to a 3in DP and use the stock elbow, most ones I have seen for sale are the 2 piece ones and they are hard to get leaks fixed.
If you can find a THDP, they are one piece and you do away with the elbow but you have to cut the cover to make it fit.
I have a high temp coated steel THDP on one car and a Mease SS on the other.
Though the SS DP will last longer, the coated steel pipe looks great.
Someone had a steel THDP for sale on the board and you could get it coated to go on your show car.
Post a wanted ad for an ATR SS 2.5" stock replacement pipe. The going rate is about $100.
With ported elbow and a nearly stock car (TA49/36# bluetops), I went 11.80's through this pipe, so for a really stock car its fine. No need for a Meese or THDP (or ATR THDP copy) which require the shield to be modified, anyway.
I replaced my stock downpipe and elbow a few months back with a 3" ATR downpipe, I had to cut the turbo shield to make it fit. I think fullthrottlespeed.com sells custom turbo shields that will bolt right on with a 3" downpipe.