As implied by the name, the championship regulations have been kept wide open to encourage all types of sports racing cars (open and closed top) and to encourage engineering expertise and flair. Open regulations also help to keep costs down. All cars must however comply with MSA safety regulations.
The OSS format was devised with the club competitor in mind. The Championship is run over 14 rounds at 7 double header weekends. Race day format is 20 minutes free practice which allows competitors who can’t afford the time or cost of pre meeting testing to try new set ups before qualifying, then 15 minutes qualifying and two 20 minute races. Entry fees are very competitive on a cost per track time basis as with all other UK championships. Another unique feature of the OSS Championship is that competitors can share a car doing, 1 race each and still compete for the Championship as a pair, ideal to keep costs down.