One thing you should consider is that any time you change or modify any vehicle in any way, you will be prone to having different issues come up from the issues you will encounter if you were to leave your vehicle stock.
So weather it's lifting it with keys, suspension lift or both, you will be prone to
wearing things out prematurely. You should do what you need to, to get what you want. If you are doing the work yourself then replacing some ball joints down the line shouldn't be that big a deal. Also, are you just trying to get a different look or are you doing this for function? it makes a difference on what you will wear out first and why. In other words, how hard are you going to be driving it. If you are just looking to get a 33" tire under it to start and don't have the high dollar lift money now, do the F keys. You will be changing everything anyway once you go for the suspension lift including going to 35" tire probably because why spend $1,600 to get an extra 1" when you can spend $280.00 plus labor to do F keys, coil spacer in the rear and new shocks all around. You can even get better upper Control arms for not to much $. check out http://cognitomotorsports.com/
BTW, I did the F keys on mine after I cranked up the stock keys and didn't get as much up as I was looking for. Cranking the stock keys made the ride a bit more stiff but not bad at all. (if they weren't made to be cranked up/adjusted they wouldn't have made it so you could do it) The F keys gave me a 3" up over stock and aren't even cranked up all the way.
In my opinion the stock ride is way to plush anyway. I used to drive a Caddy. If i wanted that kinda ride I would have kept the car.
With F keys I noticed that the ride quality was about the same because of the re indexing and the only thing that I could tell right off was that the stock shocks weren't damping enough at the top end. New diferent rate shocks will fix that.
Body lifts are for getting that extra edge after you do a susp. lift. Or for dudes that don't want to gain any advantage other than looks and are scared to wear anything out. Sheeet the dern trucks gonna wear out sometime. Specialy if you live where they salt the roads in the winter - Fookers'.
Bottom line, if you are worried about life span of parts, gas mileage or getting dirty, leave it stock and be happy your driving an Av. If not than go for it with whatever budget you have to get what you want. You will have plenty of time to do more upgrading and you will probably even get a new Av to do it all over again with in the future.
Have Fun and Good Luck!!!