Old Tubi to newer Tubi/Capristo muffler

I would say any aftermarket exhaust alone does not really add any power. where putting something aftermarket on is 99% for improved exhaust note..

the only option from experience that offers something noticeable.. is a challenge style tube only. where the difference is mainly throttle response. at full load rpms raise quite faster compared to regular exhaust..

for any little gains it offers from boltons, would be via the new headers and highflow cats or test pipes.

so to answer your question, simply switching your tubi for another tubi or capristo regardless the canister configuration, will likely yield nothing noticeable in power..