You can poll the members here and not find three that agree on exhaust modifications. Personally, I do not find enough gain for cash outlay with after market exhaust. There are some dyno tests out there that indicate one or two exhausts will chart higher horsepower readings. My own personal bike does not see RPM's that exceed the 52 to 5500 RPM range, and I think some of these dyno tests are showing most gains from after market exhaust in the higher RPM ranges. If slipping on an exhaust would gain all KLR's a four horse increase from an idle to top operating RPM's, there would be an immediate stampede of KLR riders to the parts distributor houses.
These are only my personal opinions. While up on this soapbox, I'll throw in that with current regulations regarding motorcycle exhaust, and the tunnel vision focus of activist groups on us, I would resist laying out any money for after market exhaust at the present. Unless you have enough additional cash to cover federal violations charges that may include impoundments, depending on where you get hooked. I would suggest tinkering with what you have and seeing if you don't find some suitable settings that keep you out of trouble with the law.
Hopefully Tom will pipe in on this one, as he has more experience with the GEN II exhaust systems than I do. He is a self proclaimed non-conformist when it comes to regulations and exhaust.
“many a trip continues long after movement in time and space have ceased”- Steinbeck, [I]"Travels with Charlie"
[FONT="Century Gothic"][I]Sometimes your only available transportation is a leap of faith[/I] [/FONT]