i have bought a 300c awd black cost me around 45k (with 100000mile warranty). I would like some performance upgrades and i am very auto challenged. But i know a mechanic who i trust and i would pay him to do all my upgrades. You might have a question why dont i buy the parts from him, he doesnt know nothing about the 300c. I would like get around 20-50 horses more upgraded the tires all ready(not the rims). please no exterior upgrades, like rims and grills or dashkits. just want performance upgrades.