Nice to see you've implemented several of my suggestions. Bike effect looks OK and the flips look better. Coming along well, but it isn't quite ready, in my opinion.
1) When you setVectorUp, you assume that the vehicle is travelling North to South. If travelling South to North, they spin the opposite way (not a big issue), but when East/West or another angle, they always flip end over end. You need to take into account the current direction of the vehicle, since setVectorUp is in world-space, not model-space!
2) In the flip left code, you goto "loop" rather than goto "left". This means vehicles will always spin in the same direction.
3) You don't take into account the initial ground angle the vehicle is driving over. If the IED is on a slope, then the vehicle will right itself to being perfectly horizontal, before starting to flip (_deg is initially 10, regardless of initial vectorUp). This isn't critical, since IEDs would probably be on flat ground, but would be nice.
4) The most important thing, for me, is that you are still using vehicle-specific triggers which are fine for cut-scenes, but useless for any mission. I realise you didn't intend this to be used within a mission, but it is such a simple change to make this more generally useful.
5) You set _dfact to 1 for all vehicles, after setting it to 3.4 specifically for a truck. Not sure whether that was intended, since the higher value didn't improve the effect. You might also consider flipping the truck onto its side, rather than right over onto its roof, since it is much heavier. Not sure whether that would look better though; maybe try it out?
6) The demo observer is a bit close to the explosions and it is hard to watch what is happening when you are getting shrapnel in the face ;P