Buick Regal Trailer Hitch ??

I bought a 91 Regal from a friend and I want to put a trailer hitch on it to pull my two snowmobiles. It has the 3.8 v6 so I know it will put it just fine. I looked under the trunk carpet and I seen that some had already put in the wiring for the trailer, and it all works to!! I am just wondering how hard it would be to install the hitch? Would I need a Class 1 or 2 hitch? Thanks