I live in the UK, and when I come to modify my GT I will not be turning to Roush but will be sending for parts from the USA who seem to give a lot better value for the dollar and better horse power gains with their tuning kits.
I just wonder whether they are offering this conversion as a means of trying to move a number of unsold GTs that are presently for sale in the UK for high prices. When I last looked in the Auto Trader a couple of weeks ago there was 18 cars listed and these have been for sale for up to over a year.
As I understand those cars in the Autotrader (US) are "lost leaders" and either long gone or not really for sale. Someone just posted on a different thread he is looking for a new or low mile GT, called all of those adds and mostly struck out.