MoTeC M4 ECU. This is a fairly 'high-end' piece of kit, quite early but still current and available new (£1000 ish). The serial number is post 3000 which means you can use a standard comms cable, earlier versions used a special MoTeC cable (with a matching MoTeC price tag). Currently in standard form but for a couple of hundred quid can be upgraded to 'Pro', it will then take care of flatshifting, launch control, traction control, boost, nitrous etc etc.

£550 ono