Beautiful restoration. The metal parts look extremely nice. As far as springs are concerned, I would stick to the factory parts. Some have played with aftermarket springs and squeezed a few fps more out of their rifles, but the additional stress isn't worth it. I have four FWBs and have overhauled two of them. One, I just replaced the seal and buffer and reinstalled the origninal FWB spring, since I didn't have a new one on hand. It was about 3/8 shorter than new. Another rifle, I replaced the seals and springs. Surprisingly, the one with the old spring shoots faster than the rest. Go figure.