5th Jan 06 Hello Andrew, Have plugged in tuning box have noticed an immediate change in performance with no detriment to fuel economy. Fitting of box simple even I can do it. Will try box with caravan attached soon but from the increase in power and torque that appears to have occured I feel that towing will be greatly improved. Thanks for all your help and your kindness both before selling the product to me together with your aftersales backup. Please let me know if you are going to attend any local performance close to myself so I can thank you personally for your kind consideration. Yours sincerely, Adrian