GoPro would be fun.....
You could set up a tripod and do some 2nd gear drive-bys......some strong launches from a stop (as much as your comfortable with) and then run the video in slo-mo to see how the suspension reacts.
I'll bet with that new mill you could actually "see" the rear springs wrapping up under power in slow-motion. Maybe even air WAY down and try to get one of those cool wrinkle-sidewall type shots of your truck twisting the baloneys out back!!
I have a feeling my wife is planning to buy me a GoPro for my birthday. Not sure what the hell I'd film on my truck, except the way it sits quietly on the floor.
-G