Leveling Kits

[jeefsilverado]

I am thinking about putting a leveling kit in my 05 Silverado LT with the l33 engine. I think that the truck would look good with the front being a little higher. I was talking with a customer buying some floor paint for his new offroad shop. Briefly talking with him (he has not seen my truck yet) he recommended doing a 3 inch leveling kit in the front and a one inch block lift in the back. He said a lot would depend on what brand leveling kit I wanted to go with to get an accurate idea of the lift to go with. I am not really looking to lift it too much, I would just like the truck to sit level instead of the front being lower. I would love to go taller but I want to be able to fit into my garage.
Basically the truck is stock with 17inch alloys. The only options for changing the tires would be going with a taller tires (I don't know what size they are offhand but they were just a little bit taller than my old s10 zr2 with 31s on it), going with 20 inch rims in a tires close to stock height or a little taller, or leaving the stock tires on it. Hypotheical if the front is lifted 3 inchs and the rear one inch will the stock tires look to small? I would like to retain the decent gas milage I get out of it 15-16 around town and 20-22 on the highway.
For a near stock ride how many inches would you recommend lifting the front? I would prefer not to have the problems of premature wear on the suspension, cv's and tires. What brands are out there for leveling kits and which ones have better reputations? The truck is still under warranty. I know a lot depends on the service manager and what they decide voides the warranty. I have heard for the leveling kits a lot of them will not void the warranty is this true?
Sorry if I sound like a noob but other than modifying the exhaust I have not done any mods to any of the newer trucks I have owned not wanting to void the warranty or break things on a new truck.