what kind of truck/suv do you want to lift? whats your budget? and are you lifting for performance (offroad) or for look or both?
most SUV's only have one lift option - a suspension lift (whereas a non-unibody vehicle like a pickup has two options - a body lift or the aforementioned suspension lift)
if a kit exists to lift your SUV expect to pay minimum of 2 G's for suspension components. Then fork over another grand for bigger wheels and tires. If you are going up more than 4 inches you will likely have to switch to a longarm setup - the cost escalates to closer to 3 g's.
With any lift there may be other components that you will have to upgrade to avoid expensive damage.they may include - axles or gears within the pumpkin of the axle (with correct gearing you can maintain or even improve your fuel economy so the people screaming about the environment have a little less ammo to attack you with), driveshafts, U joints, you may have to trim your fenders to clear the tires you want to run, you may want different sway bars to deal with the bigger hardware or to allow for better flex of the suspension when you are offroad. If you regear correctly there should be no excess strain on your engine or transmission - although people have been known to upgrade both for performance gains.
Is this all starting to add up in your head? getting a bit expensive huh? and thats not even touching on all the other things you may want if you are actually going offroad - like a winch, body armor, different bumpers, a roll cage etc.
I know cause i did it all. put 40g's into an offroad truck over several years - had lots of fun, but got less than 10% of my investment back when i had to sell it.
Cheaper solution- capitalize on someone else's efforts - buy a truck or SUV thats already done up - usually people have to unload these cause they need money for other things in life and like me they sell for way less than what has been put into them.
any questions msg me or call an offroad shop in your area. no doubt they can answer your questions - just be aware- as they exist to make money they will probably want to sell you something - and that may not be the best solution for you. there are a million online boards about trucks, suv;s and offroading i can recommend some if you like.
bottom line - do some research before you pour a bunch of money into it.
good luck.