Maybe not. I have the 123 KW battery, manual tailgate with no step, no spare, no desk, no rear cupholders etc. It's a bit of a weird duck, but it was a fair price and love at first drive. It does have the tow pkg if that makes a difference.
^^ This ^^You're not going to hurt anything on the truck by overloading a few hundred pounds.
Your braking will be the biggest thing - longer stopping distances. Handling will also be sketchy if you take a corner too fast though probably not too bad since that stuff is pretty dense and shouldn't be a high stack and drastically effect your COG.
Watch your tires - you're running right up against their weight rating (if stock tires) but if aired correctly near their max pressure, I'd bet on them being just fine.
Short runs I've done many many times (I once ran a yard of gravel in the bed of a 1500 pickup; that was.....interesting) - 50 miles is a bit far, but given the right circumstances, and only a few hundred lbs. over, I'd do it.
People have been overloading pickups since the dawn of time (or at least since pickups were created) - keep i mind that even the "MAX" rating from the manufacturer has some cushion; things aren't going to magically fail when you exceed it by 100 lbs. or anything like that.
Your biggest problem with these trucks may be forgetting that the load is there - I've noticed when pulling my trailer with a tractor on it close to 8k lbs. that with so much power available, its easy to forget all of the weight back there! (until it comes time to stop!)
Shoot! I forgot the 25 Flash has a smaller battery and stripped out some features.
