Before doing this please check that the higher profile tyres on stock rims will mean bigger tyre diameter, hence chances of fender scraping on turns is increased, also ur power and torque on road will be diminished as tyre size has changed.
One thing more that can be done is adding spaces to the suspension to increase ride hight and hence ground clearance. This will have very little effect on low speeds of mountains, but at high speeds the car will become a little more unstable as its aerodynamic profile would have changed.
On mod i saw long time back in some indian auto magazine was that soem one had routed their exhaust pipe to blow hot exhaust gases on the front wind screen, to defrost it and keep it clear of misting. Modern cars have demisters, so not much use now. But the fringe benefit was that the river crossings were safer with chance of water getting into the exhaust system reduced
)
