I'll dig thru my Losi stuff and see if I have any extras I'm not using anymore.
As far as good upgrades to do, I think tires and weight in the wheels is one of the best upgrades to start with. I'd recommend a set of Hot Bodies Sedona tires, these tires will work on just about every kind of rock and dust/dirt doesn't hurt their performance much. As far as weight in the wheels, I would recommend about 6oz in each front wheel and 3-4oz in each rear wheel.
My next suggestion would be to keep the center of gravity as low as possible. Instead of running a 6-cell nimh battery try running a 2-cell lipo battery around 1300-2500mah. This will still give you good runtime but will drastically reduce the weight higher up on the chassis.
Make sure to keep the worms/spools in the axles greased. I typically grease my axles after every 2-5 hours of runtime, depending on how hard I have been running it. Check the Losi Comp Crawler section on RCCrawler.com for write-ups on how to add a grease port to the axles so that you can add grease without having to disassemble the axles everytime.
If you have anymore questions, let me know. I've been competing with my Night Crawler in Sportsman class for awhile now. I think I've done about every upgrade you can to one except the Comp Crawler transmission swap.
