The top drivers from each manufacturer are invited, so expect to see the best touring car drivers there (and many of the best off-road drivers and not-so-well-known drivers as well, to fill out the class with 40 drivers). Many many famous names from the US, Asia and Europe will be there.
The Reedy off-road race was the original Reedy Race, it was held at the MnM race track in Southern California until that track closed. I can't remember if there's even been an off-road Reedy Race recently, although I know Hot Rod Hobbies has hosted a couple of Reedy Truck Races.
Invitational class drivers run 4 races per day for two days, with one race each day as the throw-out. The first place finisher in each race gets 1 point, second gets 2, etc., so a "perfect" day is 3 points. The best finisher for the past 3 or 4 years has been Barry Baker (3 wins in 4 years I think), this is considered "his" race and he'll be a strong contender this year. A bunch of other drivers will certainly be gunning for him as well, with Tamiya drivers (like Dave Jun, who'll be able to practice there every day), other Associated drivers, Yokomo drivers and tons of others who are not as well known or are from smaller teams. Hopefully the goings-on in Iraq won't keep too many of the drivers from making the trip from Europe and Japan, it's great to see racers like Masami, Hara, Drescher and others in action IN PERSON.
Certainly a race worth videotaping.
With the strong mix of pro touring car drivers this can basically be compared to the Worlds, although with a different flavor - since last year a "no one-way" rule has been in effect so drivers can actually try to out-brake each other into turns, plus premounted tires/wheels/inserts take out the oh-so-common "tire/insert war" and keep things basically level and let racers concentrate on skill instead of exotic, impossible to find inserts and/or tires to win.
For the mere mortals, there's a open mod class (10-turn limit) and open spec class (19T handout motors). These classes use the spec tires as well. Every racer has a limit on the number of sets they can use so tire management comes into play. The tire inspection system isn't perfect but it's the most workable system they can use I think and again it keeps the costs down for the regular racers. Instead of buying one set for each run you're limited to I think 2 or 3 sets for qualifying, and A Main racers can get one more set. In the old days (3 or 4 years ago), racers would show up with boxes of tires and inserts and waste a ton of time trying out each combination of tire and insert (and nowadays, wheel), or try to bum info from their buddies or other teams.
Anyway, this is definitely considered one of the THE races to watch or at least keep track of. Others include the LRP Touring Car Masters (carpet, in Germany, going on this weekend), the JMRCA Nationals (one of two Japan Nationals) and the Worlds (forget if the TC Worlds is this year, it skips every other year). These are the biggies, the ones which racers from around the world attend. The JMRCA race may not have non-Japanese drivers there but with the amount of talent in Japan it is one to watch, for sure.