Well I got it done. It played out pretty much what I thought. Two guys argued with me it wouldn't work until I told them to go ahead and get it done. It went in perfectly. Actually I'm happy things turned out the way it did using a 2½" catlessback.
I think the biggest improvements besides the fantastic tone was losing a lot of weight and my hyper-sensitive hemorrhoridal butt dyno said I gained low end torque from a better utilization of the X. It's cheaper that the full Borla catback and uses larger muffs than you get with that too. The Pypes X and Pypes collector extensions together eliminate the mid pipes so it goes straight from collectors to X to muffs in one piece. I'll be dyno-ing in a couple of weeks and compare torque curves.
I have a dB app for my Razr and did a before and after scan of the setups. With a Magnaflow X, two-24" Cobrapacks and two-Spintech Pro Streets I was about 81 dB at 10' behind the exhausts. With the new 2½" Pypes X and the two-Borla XS I am at 80 dB at idle but louder at WOT.
Still don't have a sound clip altho they sound awesome. Here's some pics of the install. The system layed out on the floor, 12" long x 3" Pypes collector extenders, smooth 3">2½" fittings, Pypes X pipe with "drive tunnel" spacing, Borla XS mufflers.
I had 3 bolt flanges welded on my SLP headers a long time ago. It made bolting up the Pypes 12" extenders a breeze to put on. The Pypes pieces are very nice including the X design and notice the extra thick flange on the collector extender. It mic'ed out at .425" thick!
The 14"x9½"x4" Borla XS were a close fit but tucked up pretty nicely.
Getting the system set up to reuse my Borla inter-cooled tips (only one on in this pic). The installer routed the tails the same way SLP does their loud mouth. My old setup had the pass side wrapped around the back of the Harrop cover. With this I got a Borla system for around $650 installed with custom bent tail pipes, no Harrop cover issues, including "mids" and using the larger XS muff. I also ended up getting the X over a foot closer to the collectors and with no muff ahead of it to damp out the pulses a much better scavenging system.