I had this pipe on a 2008 KLR I bought to ride around for a week on a trip instead of renting one. It was so loud that if I didn't have my ear plugs in just right, I couldn't stand it. Whenever I was in a town I felt I was helping to give pedestrians and people in cars a reason to dislike motorcyclists.
Had to buy a stock pipe from someone here on the forum to get the bike sold.
I will admit that with the pipe and re-jetting it had better acceleration than stock. I ride a stock 2009 now.
Ride while your body will still let you.