Burt, Since the 80's dirt bikes have gotta a little better. haha but anyways proper guarding on your bike will benefit you on the wallet and keep you from DNF's.  Like radiator braces, rear disk guard, Case guards, and a brake snake.  as you know from road racing (done it for 3 years) suspension is key to the fast lane. Stock suspension is ok, and will be fine until you want to start pushing the limits and you will benefit greatly from aftermarket build on your forks and shock. Have the great equipment to protect your body, six six one makes great stuff for everyone. This type of racing is more physically demanding then road but you'll only be racing 2 hours in the morning, as the pro and advanced rider race 3 in the afternoon. I highly recommend racing 1-2 season in the morning 2 hour race, as there are fast guys in there just wanting to brag about the wood they win and not to compete against there skill level.  but practice, practice is key. ride hard and ride safe, JAKE