The race categories for each of the three Powernights events was announced at the official launch last night.

Caterhams, FFord, Classic Saloons and Saloons at Silverstone 2nd August
MX5's, FFord, Classic Roadsports, Minis at Donington 9th August
Caterhams, FFord, Hatchbacks, Saloons at Silverstone 30th August

Full release here - http://www.motion-works.co.uk/assets...sAnnounced.pdf