I'm a hobbiest detailer and I can tell you that you need to look into Optimum Polymer Technology's OptiCoat 2.0.
It's a coating rather than a flimsy sealant or wax. It can't be washed off and is a permanent coating that is harder than clear coat. It adds ~ 4 nm of thickness and makes a huge difference in swirl resistance. You won't have to wax your car for 5+ years. Their test car is on year 7 and going strong.
You'll want to prep the car properly first. Wash with Dawn, clay, ideally polish with a DA like a Porter Cable 7424xp, wash again with Dawn, and then use the OptiCoat. This may be a daunting task and it's well worth it to pay a professional to do it for you. Go to Autopia.org and ask for a detailer in your area. It's not cheap, but it's worth it.
I have the same color car. This is with OptiCoat 2.0 and nothing else and it's really a very blah picture.
2008 Malibu LTZ v6
Black Granite Metallic with Cocoa/Cashmere
PTM bowties, 35w 5k HIDs, 6k LED interior lights
5k license plate LED light, lower grill chrome strip mod
Protected by Adam's Polishes