A 2015 bike has a MAP sensor in the intake, as well as few other significant gee-gaws, like temperature sensors, throttle position sensor and even an O2 sensor in the exhaust. Changing a muffler can change the sound, and it can even change the air flow capability (though that's vastly overblown by and large). But the sensors above measure the air flow through that engine, and adjust the fuel mixture accordingly. Nothing about the exhaust or air filters is going to change that and make the sensors suddenly read wrong and run the engine dangerously lean. The MAP sensor still judges the air flow in, and the O2 sensor is still reading the ratio coming out. Together, they keep it on spec.

Can you get more power from a tune? Yes. For various reasons the tuned value is not always stochiometric, and can be lean or rich at times. This isn't always the most powerful. A tune that sets for more stochiometric at more times will generally produce more power.

 

Of the few changes I have made, I consider the last the most significant. Go with a tune. For me, and what many others say, the bike just runs like it should. Unless you know how it should run, that may not mean anything and at least for me was unquantifiable.
Now, its tuned and I honestly feel like it is an entirely new motorcycle.
Not mentioned in any post that I know of yet, drivability.
The tune on my 14 FLHTK just plain improved everything.

 

Just slip ons? Get a set of XiEDs. You can find them online for less than $100. Take less than 5 minutes to install. Lean running problem solved.

 

Yes, a fuel tuner will help your scoot's performance dramatically. Do your homework, majority of fuel tuners require maps, & dyno tuning $$$. There are plug & play fuel tuners that plain out work for less. I chose Cobra Fi2000 with auto tune & constant variable tune. It uses your crank rotation and adjusts 80 times a second, adjusting automatically on all you upgrades, every time you ride. For me it's a no-brainer.

What ever tuner you decide, wish you well.

B Bop

2012 FLHR (Road King) Ember Red Sunglo & Merlo (stage II)
Cruise Control, ABS, Chrome Aluminum Profile Laced Spoke Tubeless Wheels, Security Package, Saddle Bag LED Lid Spoilers, and an array of accessories that enhances nostalgic appearance & blood curdling performance.

It seems that perfection is reached not when there is nothing left to add, but when there is nothing left to take away.

 

My signature has the list of mods for my 2011 Street Glide. I just picked up a 2015 Road King, and I have started to make some modifications to it.