Privacy Plus usually refers to the original Type I systems. Smartnet is a set of features for public safety users such as emergency signaling, remotely monitoring a radio, dynamic talkgroups, radio/TG ID, priority scan, and remote steering. All Smartnet systems use the Type II trunking format.
The MTX8000 will work on both Type I and Type II formats, but does NOT support the Smartnet feature set. This is why they are not suitable for public safety applications, and why public safety users use the MTS2000. The MTS2000 does support the Smartnet feature set.
Hope that helps.
Jeff