Charlie
They are a waste of money IMHO. I had one fitted , and when they did it they claimed that the ignition needed advancing because the amplifier would "see the signal earlier"
I was not convinced of this at the time , and on checking with others more knowledgable than I , think that is incorrect.
Yes there was a marginal improvement , BUT this came from the ignition advance and the car seemed to need the premium unleaded fuel thereafter.
I have since removed it totally, and can confirm it made no difference.
I think I still have it somewhere, if you are still curious and would like to try it , I will post it to you for the price of the stamps.
