hay killer, how you doin, i´ve got a 03 ktm 660 smc which is running a full titanium akropovic system made for the previous years lc4 640. I had to modify the pipe and a few things on the bike to get it on right as on this model the carbs bigger and is missing the starter motor, but have been running it for about a year no probs. I put a bigger main in it just to be careful but really dont think it needs it, as with the previous lc4 i found they are as standard too rich up top so the 165 main should be fine.I have put in a bigger pilot however as it makes it a bit more ridable at lower revs around town etc. As far as the airbox goes just take off the huge cover on the top and throw it away if you haven;t already. Feel free to drop us a line about any thing reguarding your ktm, mines got the head off it at the moment, trying to squeeze some more power out of :)))