Hey, TheBeast. I've heard from a few people (who even have D60s) that in a lightweight rig like a blazer, a nice lightweight built D44 can make the rig even more capable than a heavier D60. It just depends on the driver and tire size.
A lighter rig will be a more capable rig in most situations. Some examples where a heavier rig is better are:
Using your rig to tow out another. Simple momentum and inertia, a heavy rig makes towing something out easier.
Snow/mud that has a bottom, a heavier truck can sink to the bottom and grab a better surface.
For most other situations a lighter rig is going to be better. It's the same thing as racing a car, a car that's twice as heavy with twice as much power will always be slower around the track.
Four wheeling (other than in the mud) is ideally a balance of low COG, big tires, high clearance, light weight, etc. Of course with bigger tires means heavier axles with less clearance which is somewhat of a step backwards.
The big deal with going to a bigger axle is being to reliably run a bigger tire, with more clearance under the axle (many people make the statement that bigger axles have WAY less clearance but it's often only one tire size which is more than made up for by the bigger tires you could run). In my experience I have seen over and over, a 5000 lb vehicle on 40's will almost always be more capable than a 3000 lb one on 35's. The weight is a detriment but the bigger tires mean more.
There's always more to it and suspension setup, drivers, COG, belly height, approach/departure angles etc mean a ton
But watch a 5500 lb vehicle on 42's vs a 4000 lb vehicle on 42's and you'll see why weight is so important
