gday Steelpoint
firestone are one of the good brands
first i would look at how the ute trailer was loaded
get all the heavy stuff for the ute up close to the front of the tray or in front of the axle
and in the camper all the heavy stuff over the axle
in my set up i carry about 500kg max in the d/cab ute tray
and try keep the ball weight on the camper no more than 150kg
in the ute tray i normally carry
1 x 80ltr fridge full
1 x 80 ltr esky full
16 x tarp pole pegs and ropes
1 x dbl bunk for the kids
1x 45ltr tub with all cooking gear
1x 45 ltr tub food ect
1x bag kids toys
bag or two of wood
plus what ever else the wife wants
2 x large tables and 4 burner bbq on roof rack (all cast iron taken out and packed in tray)
1 x kayak
fishing rods
+ tow camper (this also carries a bit of gear. but also has 2 x 120ah batteries on the draw bar ATM)
with a nice level ride
IMO i would try adjusting the load before forking out extra money on suspension
Adam