I am planning on installing AMS TMP cams along with a set of Kelford Single Valve Springs (KVS11, 75lbs). I have read through a lot of information regarding aftermarket billet Mivec housings but still unsure of what the general consensus is. Does anyone know if they are still required for valve springs that are 75lbs or less? I don't want to end up with a cracked exhaust cam gear and then have a serious problem, but I have also read about people having some issues with them and then just ended up going back to OEM again.