2.25 or 2.5" catalaytic converter and Flowmaster

Hi Guys,
I just for a 95 XJ with 119K and it needs a new muffler. Since i am at it i was wondering that I should also replace the catalytic converter with a high flow one. I have seen guys recommend a 2.5" catback for a better flow, mine is a stock cherokee that i will gradually modify, so should i get a 2.25" in/out catalytic converter and then an adapter to make it 2.5" to the muffler or a 2.5" all the way?

Thanks in advance,
Ravi

2.5 all the way. more flow is better.