Your exhaust will most likely flow with a little less restriction but whether that translates to actual performance gains depends on the design of the pipe and also the way you ride ie whether you want more at the top end or bottom.
@Paul Bryant is better to advise you on that than I am.
As for sound, what’s actually “better”?
In my view, overall, a cleaner flowing pipe will probably give you a small gain in power and be a little louder but I’m also of the opinion that the (almost weird) design of the stock crossover must have some purpose. Triumph has been building bikes for a lot longer than I’ve been riding them.