Try before you buy. Tom Knapp was sponsored by Benelli, so I suspect they replaced any part that might get worn before it did. They fired him when he had an illness, and he's now shooting something else.
A friend had an SBE back in the late 80s. I was thinking of getting one and he let me use it quite a bit. I liked it's looks with the wood stock, and the way it handled. Fit me well, and didn't work worth a hoot with light loads, which didn't bother me in a waterfowl gun. Fairly stiff recoil with 3" loads. Then I tried 3-1/2". Holy cow, I swear that thing kicked worse than a Mossberg 3-1/2" pump. I am no recoil wimp, having shot a specially lightened Browning BPS 10 gauge pump for a few years until tungsten came along, but that thing was over the top for me. The newer SBE IIs have a recoil absorbing two piece stock, which I cannot stand, but it does attenuate recoil.