Are You Going To Elevate The Car For Oil Changes ?
I made low profile "ramps" with 2"x12" lumber. I made 4, but 2 would work for oil changes.
I cut lengths of the lumber, approximately 3' and 2' and angle-cut (beveled) the leading edges of them. I attached (screws) the shorter pieces to the top of the longer pieces, forming stepped "ramps" that elevate the car about 3". Believe it or not that 3" is all the extra elevation needed.
I always change my own oil. I have two Impalas of the same body style as your's and an older Impala, Bonneville, and a few other cars and found them to work just fine with all of them.
I don't like to crawl under a raised car, but feel quite safe with the car up on these flat, wide, planks. I bought 2 plastic wheel chocks that I use on a front tire to keep from driving off the front when driving up and just for good measure I place one behind a tire, even though the car remains in "Park". I use a piece of a discarded plastic tarp (about 5'x5) to allow me to slide under and access the filter and drain plug.
Also, I put together a rolling tool box just for oil changes that holds a set of sockets, filter wrenches and all the stuff (oil, filters, towels, windshield washer juice, zip lock bags, gloves, cleaning supplies, etcetera).