Since no one else has responded about the hydraulic top link, I'll put my $0.02 in for what it is worth. You will use the top link to control the scarifiers and the aggressiveness of the blade, and the side link to crown or shape a ditch with the box blade. Hydraulic top 'n tilt allows you to make both adjustments on the fly, which sure beats having to stop, adjust, stop and adjust again, etc., etc. At least I've been learning that from the forum. Top takes one scv, tilt takes another, so if you get both, you need to have two scvs on your tractor.