I would like to change my Scorpio M Hawks tyre & alloys for better comfort. Pls advise me in this regard.?

Few months back I have decided to upgrade myself from my old lancer to an SUV. I noticed one of the reviews about M hawk that it has a tweaked suspension and also ABS. It also specified that it’s the best Scorpio yet. After waiting for a few days I purchased a brand new Scorpio M Hawk Vlx on 11-2-08 .From the day one onwards I am totally disappointed and unsatisfied about the vehicles performance in terms of suspension & comfort. I am troubled with severe neck& back pain. I have droved the vehicle in the company specified tyre pressures. (32 PSI Front & Rear). I have also checked it by lowering the air pressure one by one till 27 PSI. Even I tried nitrogen instead of air .Also I have dumped 180kg weight at the rear side to avoid wobbling since most of the time I travel alone. The M&M people have tried their best to rectify this.Now I would like to replace the tyre and alloys. I am going for Micheline 275 wider tyres with nitrogen & also wider alloys next day . Pls advise me .