Hello,
First of all, remove your snorkel under the seat. I also recommend getting
two aftermarket airfilters, UNI is good and affordable. Yes, I said two, so you will always have a clean one ready when cleaning the dirty one. Call Xr's Only (xrsonly.com) and get their Competition Exhaust, and the jetting they recommend for your carb. Your bike will be quite a bit louder, but it will sound
killer and throttle response will be very crisp.
On the gearing, I went up one tooth on the rear, to a 48 tooth. Along with the other mods, my little 200 became a beast. I'm 190 and ride in soft sand here in NW Florida ( I got an XR400 now). The 200 would not pull 3rd in the soft sand without bogging down. After the mods, and gearing change, I can pull 4th and 5th easily. Be easy on the gearing changes, don't go smaller on the front, because a 12 tooth is getting small, and is not so good for your chain. Just try the 48 tooth rear, it made a very noticeable difference, without sacrificing too much top end. Good luck and ride hard.
One more thing start using Pro Honda GN4 4-stroke oil, it does wonder for your tranny, I use it in my 200 and 400 and will never use anything else. Honda HP4 is good too, but just too expensive. CHange your oil, clean your air filter VERY often, and learn to adjust your valves and tighten your cam chain, or get somebody knowledgeable to do them for you. She will run forever if you follow the above maintenance procedures.