There are many posts on VA from Scout/Scoutmaster owners who got improved performance by adding the SDS, a Walker controller or a Teres motor/contoller. I don't remember anyone who failed to notice a significant improvement.
I have an aftermarket peripheral ring clamp for my Teres. It also makes a substantial improvement. It's not so much about flattening warps, though it does that of course, as it is about deadening resonances that disturb the stylus/groove interface. With those resonances reduced overhang on every note is reduced too. Everything gets cleaner and clearer. It was a very worthwhile addition in my system.
I have an aftermarket peripheral ring clamp for my Teres. It also makes a substantial improvement. It's not so much about flattening warps, though it does that of course, as it is about deadening resonances that disturb the stylus/groove interface. With those resonances reduced overhang on every note is reduced too. Everything gets cleaner and clearer. It was a very worthwhile addition in my system.