on which one you choose. I hear the Yoshimura 77 is nice but there are others. Check the suggestion from the manufacturer some dealers just automatically assume you need both. In many cases you don't. I have a Hindle and never modified the fuel system. I have gone further with the JT air filter system and still have it running fine. Mostly the competition pipes recommend a fuel controler...
2012 RS sm5 , 998cc V-Twin 106hp DIY brake and park brake Classic Black
It also depends on your riding style, you are 100% safe with handle and akrapovic from BRP, i Hear that HMF has quiet strong reputation for reliable aftermarket muffler without need of any other mods, some manufacturers also claim that you don't need anything else yet they don't guarantee it at all in case something goes side ways, some shall i say slow riders might not noticed a need of adding fuel management system after upgrading a muffler but if you ride your RS to it's potentials i wouldn't use personally any other than those 3 mentioned just in case, otherwise you are going to fry your piston heads sooner or later. Generally when changing/upgrading one end of power plant ( intake or exhaust ) , the other end shall be adapted too with introducing additional fuel management system/unit/chip.
Added the HMF a few years ago and love it. Great price and an easy install. No need for juice boxes unless you also upgrade your air filter. Good luck.