Hey @Yangpei are you not able to swap the cats? I love the sound of mine with the touring exhaust and cats

I'm looking mainly to improve the sound, not looking to get more performance. I also don't want to spend a fortune just to improve the exhaust sound. I figured changing the rear section alone would provide the added sound quality without major expense (according to VelocityAP.com site, changing to 200 cell cats would also require new headers / exhaust manifolds).

The car is also leased, so I wanted to keep mods to a minimum to facilitate avoiding lease-end issues.

Thats new to me, maybe it's different on the 4.7 liter engine but you shouldn't need headers. Contact Stuart through here, send him a PM, he should get back to you quickly. If you don't do the headers I would suggest the quieter exhaust so that you keep it classy.

Looking at the VelocityAP.com site more closely, it looks like I can get 100 cell cats for 2013 V8V without need for headers / manifolds.

I have been emailing Stuart back / forth with numerous questions and he has been great!

might as well just do the 'test pipe' as these secondary cats do not have sensors connected. Think Stu just mentioned he's got those from another thread.

https://www.6speedonline.com/forums/...at-13-v8v.html

You can definitely test pipe it, the change in volume won't be as dramatic as on the earlier cars because you're only changing out the secondaries. It would produce an increase in volume, but may not be as much as the OP is looking for, he's talking about Supersport. In which case you'd probably want Test Pipes + Sports or Test Pipes + Touring to get to the same volume.