Exhaust headers - has anyone bought the Akrapovic one?

[Grumpy Goat]

Do they make any difference - either on a stock or remapped bike...? 

Just wondering...

Full disclosure ... I do not have headers or any brand, so this is just my opinion on breathability mods in general. 

Yes, by definition they will make "a difference" and hopefully it's a difference you are happy with after spending the money on it.

I have a K&N filter and also a Remus Hexacone titanium muffler, installed at different times. After each installation, I felt an immediate increase in throttle response and a small decrease in fuel economy, i.e. it used more gas as the stoichiometric ratio was adjusted by the computer to account for the increased incoming airflow. There was no appreciable difference in low-speed throttle behaviour and control. I have no idea how much of a gain in horsepower and torque resulted, nor do I care, and I explain that in the second to last paragraph below.

Overall, the fuel consumption dropped from about 47 mpg.US to about 44 mpg.US, on average, all the time. I ride long distance from time to time, so a loss of 3 mpg is not insignificant. Over time the butt dyno got used to the feel of the increased breathability, and the bike is very lively and performs in a pleasing way for me.

One other difference that I did experience is the exhaust sound, with more pops on deceleration and a more raucous sound in general that is not overly obtrusive during long distance cruising. So, this is an "upside" of the muffler, which incidentally was only marginally lighter than the stock can.

So, it comes down to return on investment for you. If you add the headers you should also get more airflow over stock and coupled with a reflash I expect you will get some more horsepower. You will almost assuredly lose fuel economy and whether or not that is important to you, it will still be a tangible difference. Will the increase in power be sufficient to justify the expense - again up to you. 

I personally don't believe in big-expense add-ons to get marginal gains in performance that, if measured on a track at our typical skill level, might result in a small lap time decrease. My preference would be to put the money in a different bike, but that is just me. If one is locked into one bike then the perspective may be different. Speaking of which, most modifications have neutral to negative impacts on resale value, but I suspect a set of Akra headers with reflash may have a neutral impact, i.e. on an RS I can't see it having a positive influence on resale value, despite the fact that it "looks good on paper".

So in summary, its the intangible differences that may be more important ... if the sound and feel are pleasing then the cost may absolutely be worth it, but that is an individual decision. Sorry if I tend to sound like a buzz-kill ... just sharing my limited perspective based on my own upgrade.