Garth,
Awesome piece of gear, the 4in1 is going to serve you well, that is for sure.
Only reason to raise the weight box would be if terrain dictated to keep it from bottoming out. You can even use large stones from your property in the box until to take time to get your sand. A few hundred pounds of stones from doing general clean-up , that you would do anyway, will certainly make a difference.
GrillGuard/BrushGaurd is also on my list, in fact, it's NEXT on my fabricate list. I've been loading woodchips into my trailer the past couple of weeks, and each time I get the nose close to the trailer, I say "Drat, shouldda built that grill guard already!"
Nice machine you got there, keep the pics coming!