Cool! I'm here in Houston and hit San Jac and Cycle Ranch most often. It's nice to know that I won't be the only yellow 250 (that's not 8 years old) around here! I walso like to go to Swan when they have a big race. There are lots of fast guys on RM's up there.
Eric is 100% right about the jetting. I raced last in March and my bike was running awesome. I broke my ankle and was out for 3 months. I rode a couple of times in June and it ran pretty bad. It was the temperature and humidity. It made a BIG difference.
I have not done the head mod, but I did notice the exhaust valve thing when I did my top-end last month. I will probably smooth it out next time.
As far as the suspension, it needs a little work. Stock, it bottoms everywhere and if you turn in the clickers, it get harsh, quick. I weigh about 170 and J/M Racing was able to revalve it with the stock springs. Any heavier will need new springs, though. It's night and day better with the revalve. Good luck and see you at the races!!