looks decent, though that hdd will not fit in that case, and neither will the power supply. unfortunately, there are not any car-computer type cases that will fit the m4 or a 3.5" hdd.
i have read of some people using the m2 power supply with similarly powered setups with few issues-- it might be worth considering.
- after personally using a 629, a low-brightness transflective 669, and a high brightness 669, i believe that the standard high brightness 669 screen is one of the best cost/feature ratios around without stepping up to a transflective unit.
-not all psu's have the 4-pin power connector, but you would then use a molex-to-4pin adapter. in your case, all the psu's that would work with your higher powered setup should have a 4pin power connector.
-all screens send the touch signals via a usb cable. i recommend running at least 1-2 extra usb cables to the front of the car. they can come in handy later.
-can't answer the last one-- i cold boot my pc(i use a ssd, so my boot times are less then 2 min)