[forcefed]

Originally Posted by SwankPeRFection

You realize that exhaust flow through wastegate timing changes is how all that works, right? Higher flow downpipes are usually required for any Stage 2 tunes because exhaust flow characteristics need to be taken into account and additional exhaust temp raises is also another side factor to contend with, but mostly it’s back pressure vs wastegate duty cycles that play a big roll on all that.

You're making it sound like the stock cats are a restriction and will melt or something, but then TopJimmy is running fine with them and you still think you need a downpipe.
Have you measured the exhaust temps and back pressure? Ask the tuner what the exact changes are between stage 1 and 2, and if its just timing and boost then that really doesn't require getting rid of the cats.