I bought the carbon fiber driveshaft as soon as I read the articles on the Sport Compact Car Z build. (along with many many other parts they recommended at the time. This car has most of those parts.) I have had no issues with it. I think I weighed it before I installed it. It was like 12lbs. The stock driveshaft weighed like 60lbs. If I remember correctly I bought it from ACPT. As for the recirc valves, they are gone. I have a very old HKS blow off valve kit that came with cast pipes and the valves. The 18G's are external waste gate.