Are you sure that the DSATX can handle a Pentium D? I know they are pretty power hungry. Or do you mean Core Duo?
Seems overkill, but if that's what you're going for good for you. I am a little concerned about the power though.
Also I use M$ S&T and I love it. Many people however hate it for many reasons. It has small checkboxes and such, so not touchscreen friendly. Also when giving you driving guidance, it just says "Turn Left in 0.2 miles", not "Turn Left in .02 miles onto Bakalakadaka Street". So you sort of have to know where you are with respect to the GPS and actual streets to tell when to turn. I don't mind, but those are the prevelant opinions.