i have a paid for 02 2500 4x4 extended cab. i am considering trading for an 07 3500 srw. quad cab. it would be too dificult if not impossible to back in a drw in the side of oour oplace. with our 33' alfa trailer at my skill level anyway. all the sales people say the only difference for 2500 a nd 3500 is the heavier rear springs. the newer trucks have better transmissions,more powerful engines. and better brakes? is the new truck worth the $25000 vs $3-$4000 in upgrades to mine?