I have a sportsman 90 four my son who is slightly outgrowing it. He's not ready for a full-size quad yet so I was wondering what options are available for upgrading the sportsman 90. I have seen big bore kits but don't know exactly how much extra power they will produce. Has anyone installed a big bore kit on a sportsman 90 and if you have what were the gains? I'm also looking for suspension upgrades and tire upgrades does anyone have any suggestions? The front shocks squat a lot when he rides it is there anything out there stiffer? Thanks for the input.