Sard are steel. I don't remember what the greddy is. Have not heard of threads coming off except for the mishimoto garbage. I know exactly how the pcv system works and for my motor, I don't need it. You can vta both lines and delete the pcv valve with no issues. It's not mentioned in vfaq because it's outdated. Moreover I'm not trying to catch and trap oil or vapors I'd rather just vta under the car and get rid of the restrictive pcv. Their is surprisingly not much to catch anyway. I introduced Saikou Michi catch cans to this forum when they first came out. I have a SM dual set up on my other vr4 and they are vta as well. Just got these cusco bits in. Freight was ridiculous. Any tips on how to polish or clean up aluminum?