The Euro bar bend is my favorite and I put it on all my bikes. Because of the way the ends droop down slightly, I think these are about the most comfortable bars on the planet, lol. Those drooped down ends turn your wrists to a more natural angle compared to bars that stick straight out.
As mentioned, about the nicest muffler available for these is the Commando. But don't buy them from MikesXS, they sell an EMGO version with EMGO guts and just the Commando outer skin. Plus, they only come in a 1 3/4" inlet size so you need to fit those reducers (and they always leak). The headpipes on these have a 1.5" O.D. so that's the size you want for a muffler that will slip right on and fit with no reducers needed. YamahaXS650.com sells the old, original Commando with a 1.5" inlet. This is the original designed and developed on a dyno by Heiden Tuning. It has a somewhat tunable baffle with a removable center plug bolt .....
https://yamahaxs650.com/product/commando-style-megaphone-muffler/
They also sell some nice 1.5" replacement headpipes .....
https://yamahaxs650.com/product/xs-performance-chrome-1-5-od-headpipes/
You can replace the entire exhaust system for less than $250, quite a bargain really.