Just installed a pair of Pro Touring slip on's Running with a stock head pipe and without a tuner. The heat from the CAT has not bothered me so I didn't see a need to decat or go with a new head pipe. Bike seems to run just fine but I don't have a lot of miles on it yet with the new mufflers.

Will I gain anything by adding a tuner ? I'm happy with the power with the stock tune. Will these Pro Touring pipes flow more air than the stock CVO mufflers and make the bike run even leaner without a tuner ?

 

You may gain a little power by adding a decent programmable tuner and then running a couple of self-tuning sessions with it, and the slip-ons do have the capability to flow more air but as long as the cat is still in the head-pipe they're still pretty restricted, so the engine won't be running any leaner than before.