I purchased the HOT CAMS Stage 1 cam for my '93 XR600R last night. I am waiting on it's arrival. I plan on pulling the head to replace the valve guide seals, do a valve job (if needed) and replace piston, rings, wrist pin, and w/p retainers all in one shot. I was wondering if the cam replacement will require re-jetting the carb? Now that I have the cam coming, should I buy one of the high-flow side covers-the type with the screen inserts? The bike already has a K & N air filter on it that was installed by the previous owner. The bike is being shipped to me so I don't know if the snorkel bypass mod has already been done. Heck I don't even know if this bike came with a snorkel on the air cleaner. Regardless, if it has a snorkel, I will bypass it, or remove it. What about an after-market exhaust? Should this be my next step? I have heard that the exhaust should have been my first step, but the bike is burning oil pretty badly so I knew I was going to be doing top end work 1st, so I decided to just go ahead and do everything on the top end all at once. I would like to get a stainless after market exhaust as the stock one on the bike is missing the heat shield, and is rusty. How much should I expect to pay for the header? What about a "slip-on" muffler? How much should I expect to pay for a different (preferably smaller) muffler? Are some better than others? Which is a good one at a reasonable price (under $200 is reasonable to me). Any other updates that I should consider at this point to make the bike more reliable, and have more power? I must admit when I had my old Yamaha TT600 I tried to find performance parts for it but there really was not that much available. I like that you can find a plethora of performance parts for the XR's..