ive been trying to contact web cam and im having no luck so ill ask a few quick questions here in the forum. first question: is there a core charge for the tw camshaft? #2 the cam core listed for 121$, is that something needed for installation? #3 the valve spring kit is listed at 90$ per set. then it says the number 2. do you need two sets? i was thinking one for the exhaust and one for intake, but im not sure. im just trying to find out before i buy so i can get the right stuff the first time.