Like they said, leveling kit wasn't your best option. But, if you already have it, you might as well use it. They are fine as long as you stay within the limits of your suspension. This means keep your lower control arm and CV shafts at reasonable angles. The issue with these leveling kit as are they do the same thing as cranking your stock keys, but they also give you the ability to go way beyond the geometry your stock suspension was destined to run at.
As far as tires go, a 32" tire will fill up the wheel wells nicely and still give you plants of room for suspension travel. An all terrain tire will give you that more aggressive look you're after while still being well mannered on the road. There are a lot of choices. A lot of guys like the bfg T/A ko or ko2, I loved my Hankook Dynapro ATMs.