I have a 2005 Mini cooper s. Just bought 15% reduction pulley, new gates belt, and colder running ngk iridium spark plugs. Two mechanics in my hometown have both asked, "Why am I doing this?" When I tell them why they tell me this is not a good idea to do, as I am "opening a can of worms" and will cause "trouble down the line."
Ive read about many that have these pulleys with no problems, am very frustrated,
Has anyone had any problems with their mod and am especially wanting to know if the Mini ecu compensates for the changes?
recomendations please and thanks

 

Its will not harm the engine. Its fine with the ecu.