I'm actually receiving the HD today, hopefully I'll have time to swap it out and test if starting up speed is noticeable. I'll most likely do the same and keep the stock HD in an enclosure. I'll also let you know about heat/battery life but I haven't test the battery life except once (lasted for 3.5 hrs with wireless on and internet browsing, brightest setting, BT enable for 30% of the time).
EDIT:
Took 20 seconds to show the desktop and another full 10 seconds to load Quicksilver and show all the icons on my desktop.
Cool - look forward to hearing how you go. Great to have the 'as it happens' accounts! Much obliged.