i will do 178 pulley but in the future, now i want just to start with SC pulley because, i will no need to do ECU chip tune for it. I do not do ecu tune because our best fuel is 91 octane but it is not that good quality like yours that is why i am afraid to waste money. evosport. told me there is no point to do ECU for me because of low quality fuel in our country. And Kleemann told that if i Put 178 pulley with out ecu tune there will no gain HP cause of ECU on C32 AMG can not adapt it self for increased boost. i am talking about AIR/Fuel 1/14 proporsion, by puting 178 crunck pulley i increase boost but level of pumped fuel will stay the same , tell me if some one installes 178 pulley with out ecu tune and achieves power, i will do the same. actually one car shop service told me, that adaptation is available by MB dealership Diagnostic computer. tell me if it is true. About vendors, who do you suggest? you know you live in US it will not meke you big problem if something wrong with item in my situation it is a problem to proofe to a Seller being their product not working and get change or even refound