The difference between the Autoglym series, which was sponsored by the car care product manufacturer, and the D1GB is that the former had a separate championship for beginners called Clubmans which was run in a tansou (solo run) format only and did not require the common safety amenities (e.g. rollcages), and the latter is a main championship for experienced drivers which consists of the usual tsuiso (twin run) rounds. The other difference is, D1 regulation is more stringent on car modifications. The club was since absorbed into the D1 franchise as a national series.
