does import cds sound better

SHM is not a process, it is a material which IMO slightly enhances the clarity of the top end. It has nothing to do with mastering or remastering. If you think a title currently sounds anemic I don't think SHM could help, possibly doing just the opposite. I personally would steer clear of early CDs in this format but you should experiment and check a few out for yourself. My opinion is purely hypothetical. Who knows, they may sound OK.

Thanks very much for the explanation, Rja. I just assumed they would do some EQ or cleaning up the tracks. I guess the reason for the debate over this format is due to the fact that many doubt a new material will make a difference. I will listen for myself.
(and Aja is an excellent reference recording).

Not countries, but labels. There are a handful of labels producing consistently high quality recordings and music. Both are important, for example, I like Naim recordings, but much of the music is, well a bit tedious:

ECM
FIM
MA recordings
Reference Recordings
Stockfisch
Are my current favourites for CD/XRCD. Of these Stocfisch would be number 1

Super High Material should probably be Super High Transparency Material inasmuch as the clear layer is a special polycarbonate formulation with higher (optical) transparency than the standard stuff.