Bazzie;
I first installed on 2014 GSLC Rhemus headers, original slip on and the ACCELERATOR MODULE without the temperature sensor that I had purchased a couple of years ago for 2011 GS (
http://www.sol2.be/)
The results were:
Better torque and therefore accelerion. If I would have to quantify I would say the performance improvement was of some 4% overall using my assdyno... Noise wise it become also a little bit louder.
One nice advantage of the Rhemus is that its original color turns into a very light "champagne" or very light gold color and STAYS THAT WAY !
Last week I installed the BMW AKRA. The improvement was, again, some 4% on top of the previous mod! Overall the bike is quicker and livelier. I would be surprised if a dyno run doesn't shows some 8 to 10 hp and at least a some 5 Nm torque improvement.
Sound wise it is throatier and louder but, as far as I am concerned, not too loud.
Checking the ACCELERATOR MODULE website I found that they make a specific GSLC unit and I ordered one; perhaps it will be even better than the one I am using from and for a 2011 GS. I also plan to use a K&N air filter but haven't tried it yet.
Please consider that in Brazil where I live we have 25% alcohol in our gas and I don't know if the results I obtained will be the same that when using pure gas.
What I can say from my experience is that performance wise it was worth every cent spent and then some... Noise wise I am very happy too but this is something very personnal...
Andre