You have to start with a baseline.  Is the air filter clean? Has the carb ever been touched by an amateur?  If not, find out what size jets are installed now.  They have changed over the years. Don't use vented pilot jets - ones with holes in the side.  If you do, all bets are off. Pull the spark plug and see if it is blackish - too rich or whitish - too lean.  How does it act when riding, hesitations or flat spots?
I'm not fond of open pipes. Gives riders a bad rep. Attracts police. A Harley Dyna muffler is mellow and not expensive - usually $20 good used on eBay.
Generally, if the carb has not ever been messed with, start off with small changes, maybe go up one jet size. Trim or shim the white spacer to half it's stock thickness. Don't go overboard.