Hey guys, I finally got around to getting the cats installed today. I went to a local shop, the same guy who did the Disa tips on the beast for M5Guy, and had them install the cats in place of the stock resonators. The Mil.Spec cats are pretty small so they had to fabricate the extra pipe. I didn't get pics on the lift so took them when I got home.
The sound did change slightly with these on. The turbo spool and exhaust note is still very strong, but very slightly muffled. The only real major difference I noticed was the reduction of the garble when letting off the gas at high RPM. It's still there but sounds a little better; loud but refined. I'm pleased.
The smell was the big change. I've been driving in forward into my garage since the catless DPs but yesterday backed in and it was aweful when I hopped out of the truck. Today when I backed in I could smell it, but barely. When out and about I couldn't smell it at all. I parked outside, let it idle, took a knee next to the pipes, and couldn't smell anything. It's likely just closed areas that you'll notice.
I held onto the stock resonators and was surprised how little packing they have...pretty much just straight pipe with a thin single layer of packing. Picture is out of focus, but you can see a bit on the adjacent resonator:
