Oh I like, installed racechrono at a price I like, free, looking at their website these 10hz qstarz bluetooth to your phone for more accurate timing. http://www.trademe.co.nz/electronics-photography/gps/automotive/auction-556991502.htm
Racechrono already has Manfield in the track listings, already set up with split points and start/finish loaded
that makes for some pretty cheap laptiming, or for $200 you can get a flasher one that you can dump onto your PC and analyse later.