I am having the insert installed by a dealer. But, what things should I make sure of? I am getting a 35 foot liner kit. Do I need to make sure it is insulated? If so, why? Do, I need to insist on anything else? Any advice would be greatly appreciated. I have finally found someone who will install this and I just want to help insure it will go in correctly. Thanks. BTW, everyone still happy with theirs? Thanks.