Well, I've ridden my share of bikes with full exhausts and no tunes.
Plenty with Power Commanders with base maps, and the base maps all suck, with the exception of Brocks.
No noticeable change in smoothness, idle, hp, nothing. Get a brocks exhaust and get their base map and you'll have a much improved bike. Otherwise, I wouldn't waste my money.
If the bike runs good and the sparkplugs look good, then it's running ok. The plugs tell the story. If they're lean and burnt or rich and sooty, then you need a dyno tune.
Will a dyno improve it? Of coarse! But not everyone has access to one either.
I've said it many times; Where are all the ruined engines from a full exhaust with stock a/f? Where are all the posts on various forums about them burning down? There aren't. Finding a handful out of countless thousands proves nothing either. Then you need proof that just a full exhaust alone was catastrophic.
Again, dyno tune whenever possible! But worry about not doing so on a stock engine? Nope.