What you can do is put softest tires available in the market! Like perreli, Dunlop or yokohama etc. If ur using General XP II 2000 u need to throw them away.. theyr patheticest tires avaliable in the market! took ride in a coure with stock tires and know how it feels like! PATHTIC!! Too much road noise and the body vibrates and shakes on every single crack on the road!! :S
Donot try to change suspension! And who told u banging ur ride on every hump wud soften its suspension!? Over loading it like a suzuki carry daba and a school van might weaken the hard spring but not banging it arround like this!! This wud not do anything except ruinning ur shock absorbers! NOt the hard springs!
Well and nothing floats above the ground like a suzuki so u wud definately feel the diff! suzuki = 60km/Hr and ur ride floating in air