Well done, and congratulations. It takes all of us time to get our bikes the way we want them, new or used, and really that's half the fun.
Surging at idle? I'd start by cleaning out the carbs and gas tank, and giving it a service. How many miles has it done?
Factory pipes AND loud? They normally don't go together, quite the opposite in fact. Chances are the pipes have had the baffles gutted (which might also explain the surging if he's not had the carbs re-jetted etc to suit). There's plenty of good aftermarket pipes available, it all depends on your desire for volume and your budget.
