On most bikes that I've owned, I have installed an aftermarket exhaust sytem to improve sound and performance. In most cases, this has been successful but a few times I have found that performance suffered.
After a fairly extensive search, I decided on REMUS slip-ons for my V-Strom. They are available from Max Moto in San Francisco (415-355-1400). Quality of these units is excellent and is reflected in the price of about $700. Installation was straightforward and they look and sound great. REMUS claims +6 HP at higher RPM's. As they put it, sound is about 30% greater than stock but not "juvenile". They were right! The sound is just what I wanted but not so loud that it is annoying on trips. In fact, it's so good that I don't even want to listen to my portable MP3 player. I just want to hear that V-twin music!
I would highly recommend this product to anyone who is looking for a top quality product and a greatly enhanced sound. [/b]