I did exactly one test drive with my wife and son, in the configuration of car that I was interested in (85D, 19", solid roof), and what we ended up ordering. Our Owner Advisor (from the Walnut Creek, CA store) had both of us drive the car, on the freeway and on surface streets.
As a number of other people have said, there was absolutely no pressure at all from our Owner Advisor...he seemed genuinely interested in making sure that we learned as much as we needed / wanted to know. I'd already done a bunch of research (including a lot of time on TMC) so it was pretty clear to me what was right for us. After the end of the test drive, my wife and I made one small tweak to our intended configuration and put our deposit down. (We, alas, had to veto my son's proposal to go for a P85D.)
OK Navyguy, now having gotten a bunch of us to tell you our stories...we're all looking forward to hearing how your test drive went!