Andy - I know I'm biased but the only class of buggies you need to worry about is the Quicksilver class mate

Last year it was raced as the Retro Racers class but for this summer it's being opened up to any buggy with a stock Tamiya 540 motor in it. Your Scorcher will be more than welcome to race. I raced a Beetle bug myself once and would love to see a Scorcher having a go. Pretty much anything goes chassis-wise, we've raced Lunchboxes, Wild Willy, Subaru Brat , Trucks, 2WD buggies, 4WD buggies, ex-race cars such as RC10s and Yokomos and "starter" cars like Hornets. For this year I've just picked up a Holiday Buggy
Roll on Summer I'm looking forward to the racing already.
Richard