i seen in another thread that there is a gasket between the manifolds and midpipe? i bought my prochamber used. what do i need to get and where do i get them? also they said that one of them is metal, my car has like 3000 mi on it, would the stock one be ok, or is there one stock? also they were talking about getting new studs? i just want to cover all bases before i rip the stock off.