I already have a factory fit PSE so for the powerkit I have been quoted Pounds8360 and Pounds8550 with the short shifter all in (VAT & labour). OPC West Sussex seems the most keen on doing these. They claim to have done 5 retro fits which is important as a few others I had called were more expensive and had not done any! They have also given me the details of people they have done it for (with their permission ofcourse) so I could give them a call and have their thoughts on the changes the powerkit made.