1) Re Rod's high EGT's - maybe a good experiment for less than $100 shipped to his door would be to fit a muffler delete pipe and see if the improved exhaust flow decreases this high EGT problem. If it cures it, $100 fix! If it improves it but not by enough, at least you have much better confidence that a 4" turbo back system will improve it even more!
2) Been reading a post about a US guy who's turbo shaft snapped! There was a comment that this problem could have been caused by 'imbalance' caused by having a high-flow air cleaner, a 6637, and the stock 3.5" exhaust (LIKE I HAVE)!
1. Its Loaf400 (Rod) not that Rotten bloke I believe he has a straight through muffler. Just get the 4" and be done with it.
2. Its the first I have heard of it. Got a link. Could be a number of things,