Exhaust clamps for lap joint 1.75?

maybe i just found something at O'Reilly. made by ROL gaskets? so if I get 2 of these, then get 4 u clamps, I guess I would be set up? Is there any sort of sealer I should use? [+] CHEAP Rol Exhaust 2.00inch I.D. x 1.75inch I.D. Reducer - 548503 For Sale

I cant afford to take car in to have welder deal with it. though the cost of the fittins and clamps going to be about $18.