I found what looks like a good deal on an FMF Powercore 4 slip on, this morning. FMF has different part numbers listed for the '06 and '10. It looks like they used the same pic for both pipes on their site, and the only difference I see in specs is 0.2 lbs less weight for the '10 pipe. Will this pipe fit my '06 without much modification?

 

Someone??? Anyone???

 

It should as long as everything is for/from a KLX250.
My first go at an aftermarket pipe was a KLX300 header and FMF off of a '99. It bolted right up. But was not interchangeable with the 250 parts.
You should get an extra pipe gasket, just in case you need it.
I hesitated responding, obviously, because I'm not 100% sure...haven't looked at parts drawings....but in all the threads I've read, only the 300 and 250 have different size/shape headers...which by logic also means (thin ice warning) the 250s are all the same...cough, cough.
FWIW, I found my 300 PowercoreIV was headache inducing loud, but it did not have the quiet core insert. It did make all the Harley riders stuck with their cages turn and look. I prefer to keep my whereabouts unknown off-road so I took it off in favor of a stock KLX300 muffler I got for $35.

 

Thanks for the info. I'm not into loud, either. I had a piped Electra Glide one time, and after a while, even I started to confuse the noise with actual power. I don't want to do that with the KLX. I just thought for $150, it would be a relatively cost efficient way to get a little grunt out of the runt. Maybe I'll just hold off until I come across a 300 pipe, like you did. I should start looking harder.

 

I saved a search on e-bay for klx mufflers and pipes. Took a while but with patience I was able to get a nice one in better shape than my stock muffler.