Thanks for pointing out the snafu about the active antenna. The GPS specs seem fairly complete but make no mention as to what type of antenna is used. You've convinced me that erring on the side of caution is the best route, and I can't imagine the heatsink should be too expensive anyway.

One other thing I noticed: the 5V PSU schematic also calls for a 100nF capacitor. Is that not needed in this application?