Lowering A 99 Escalade

I Am Helping A Friend Of Mine Lowering His 1999 4wd Escalade. He Just Wants To Get Rid Of The Gap In Between The Fender. We Were Just Wondering A Few Things. First Of All If We Lower It, Is It Going To Affect The Ride Quality(it Has 274-45-20's In It)? Also How Much Higher Does The Rear End Sit Than The Front. I Heard A Few People Say That You Can Use The Stock Torsoins Keys To Lower The Front 2 Inches, Is This True(a True 2 Inches)? We Were Looking At The Belltech Kit 2/4 Drop,torsion Keys,hangers And Shackles. Will This Kit Make It Sit Level? Any Other Suggestions Appreciated. Thanks For All The Help: