Since you are getting a rebuild check with the shop for what they recommend. Since it will have some sort of warranty. Just get a size/style recomendation from them and buy it yourself to cut out the markup.
There are a few different styles/sizes available. All that i have seen come as a kit,with mounting brackets and hardware.
I used a cooler rated at 24,000GVW. It was the biggest one i could find locally.