I have a very heavy 4th gen with a V6 and you definitely feel the weight. I am running front and rear steel bumpers, skid plates, sliders, dual batteries, rear drawers, fridge and when I am on trips I usually have ~15 gallons of fuel and ~15 gallons of water, so it gets really heavy.
The truck does fine, but if you are running weight like this and bigger tires you would really benefit from a re-gear. If you are towing, that is even more case. I have put it off for way too long, but really should do it myself.
Which gear ratio are you gonna run next?
Most likely 4.88, but not 100% sure yet. Keep going back and forth between 4.88 and 4.56. The truck isn't my daily driver and only gets used on camping trips, so I can handle higher RPM's at highway speeds.
I've been considering steel front and rear bumpers on my 08 sport. Other than the obvious need for heavy-duty springs, are there any issues with overall weight? My biggest concerns are on wear and tear on transmission, inability to accelerate w/ a trailer attached, etc.