any lift over 2 inches is going to run into money.
a body lift is the cheapest any suspension lift will cost.
you really do not want to cheap out if you plan on running trails with your rig.
If it breaks you are done....
fender trimming 90% of the time involves the rear edges of the fenders front and rear.
1-2 inches back and 3-4 inches up
you can sawsall a lot of it back and them hammer the edges flat and smooth.
when the tire is turned and travels up it will contact the fender
all vehicles and tires are different so an exact measurement would be difficult to give to you.
bottom line advice is , if you decide to put in a large lift do a body lift and a good quality suspension lift . 4 inches you can squeak 35s but trimming will be needed.
also the added lift and tire size will put more load on the front axles and cvs.
Hope this helps