Originally Posted by The Mass
Try a search for WINGS mufflers.
They are made solely for KTM's and are a class piece of work. (Dare I say....equal to an AKRO)
The Oz importer is MOTOTOYS, he doesn't list one for the 640 anymore, but there might be a few flying(get it?
) around somewhere.
I have WINGS on my 990 SM-T (it's really fantastic: quality, weight, price, everything is top-notch!), but the muffler for 640 out of production for a pity.
I personally know producer (Gorazd - stand up guy, he helped me know his country, very friendly with a beautiful family) and he says that for a pity it's impossible to get one on my 640 Adv.