I was got the above mentioned muffler from a 95 KLR for $20 yesterday. I installed it, and what a difference. It was in fairly good condition, and mounted up to my 2008 perfectly. I found no issues with it, but did spray it with a flat black high temp paint, and it looks great.
The bike has really responded well to the stock exhaust, no more obnoxiously loud exhaust, no more popping at all, and a very smooth power delivery. With the FMF exhaust, anybody within earshot turned to look as I would accelerate, now no one gives me a second look, exactly how I like it. Staying under the radar means less chance of any interaction with the local police, or not drawing the attention of the Rangers while on the forest roads.