77jovian,
Blu-Spec is a process of manufacturing where a blue laser is used to. I believe it's like the process used for Blu-Ray DVDs.
SHM-CD is a super special material used to make the CD. It is usually a good mastering in addition to the material used.
SACD is a higher quality resolution recording. Blu-Spec and SHM-CD are both normal CDs.
Chuck