FYI. The retrofitted epas offered by a couple of AM dealers for around ?4000 is the same unit as used on a Vauxhall Corsa. The unit is very small and fairly simple to fit. Many TVR owners have already fitted the system to their cars with great sucess and I know a few Bristol owners are also looking into it. The unit is available for very little money and needs to be used with an addition controller available here . The tricky bit is welding it into the existing column, this should be left to a specialist engineer / welder. Apart from that it is a case of securely mounting the unit behind the dash. I believe it will work with positive earth and on a dynamo system.