Interesting stuff. For the manuals I've owned in the past, I've never parked in gear and just relied on my emergency brake. After reading this thread plus the manual, I'm definitely going to rethink things (even though it's flat here in Houston!).
The manual says for manual transmissions, "shift lever into reverse and then apply the parking brake. With the clutch still pressed in, then turn off the engine."
Order date: 7/17/09
3000 TPW: 8/17/09
3400 status on 8/11/09
4200: 8/24/09 on rail car ETTX850796