I'm considering a minor lowering kit (2/4) for my Yukon XL to help with looks, body roll, etc. I'll probably add an aftermarket anti-sway bar. I'm also considering other options to improve the overall ride quality while I'm at it. Given the length and weight of the truck, I must admit the stock ride quality is pretty good. Can it be improved significantly (i.e. to justify the expense) with higher end aftermarket options - e.g. air bags, coil over kits, etc.? Is air suspension over the top for this vehicle? If so, any aftermarket parts/systems you'd recommend?