Ok so my exhaust is turning into a mess of miss sized pipes....So i need some idea of whats going to work and whats not

Right now i have the Stock LS(GS,RS) Exhaust manifold, A pipe, Cat...that goes into a USDM ITR B pipe...Which is CURRENTLY going into a Stock LS Axle back Muffler

Now i saw a JPN ITR Axle back muffler for sale here...

I know its been said 100,000 times that this will all fit together and bolt up....But i know the JPN has a different(smaller) cat so there is a difference in length SOMEWHERE down the line to make up for that...

Is the difference to compensate for the shorter cat in the A-Pipe, B-Pipe, Axle back Muffler? A combination of those? Will bolting a JPN ITR Axle back muffler onto my setup work...or will i somehow end up to short(or to long) somewhere?

 

Think i found the answer

https://honda-tech.com/forums/acura-integra-type-r-8/will-jdm-itr-axle-back-bolt-usdm-itr-midpipe-2243687/