Welcome to the wonderful world of RGB. This is a race series for cars powered by 1 litre superbike engines. This gives a quite astonishing level of performance without doing terminal damage to the bank.
To put things in perspective, the RGB lap record around Brands Indy is 47.98 seconds. Compare that with the BTCC record of 48.50 seconds. And, the RGB time is on road tyres, with no sophisticated aerodynamics and without the hundreds of people and all the associated expense and complexity. Best of all, the 13,000 rpm engines make just the right noise.
RGB is owned by and run under the auspices of the 750 Motor Club, long the home of motorsport for, as they said in 1939, the “impecunious motorist”. There are many details about the championship on the 750 Motor Club site specifically about RGB.