lots can be done to them, depends how far you want to go. you can fit mud tyres, but maybe they stick out the arches so you fit a lift kit, then the tyres still catch the arches so you cut the arches out...then you get stuck anyway so you fit a winch......the list goes on and on. best bet is get to a local pay and play site, plenty of people there to offer advise and your never far from a tow out if you need it. find a level of off roading you are happy with and mod your vehicle to suit. ie its no use making loads of mods to your vehicle if you scare the life out of yourself trying to use them to there capacity