you guys have probablt read this 1000 times before... am looking to get my a3 chipped, and i know a guy who does car diagnostics/mileage correction/fault codes etc. He says that he can remap my car to 170 BHP with his equipment for £250 which is obviously cheap. would you trust this? or is my money better spent with a 'proper' company? and who would you recommend? i want the most power!