Lyco have finally done away with the really major weakness which was their "disappearing tappets", by bringing in roller tappets. But they have ensured that you need new crankcases to have these, which ensures that it will almost never be an economic retrofit.
IO540 - I believe the roller tappets have not necessarily fixed the camshaft/cam follower problem and from what I understand the rollers are still rusting and seizing.
Stand to be corrected!