O2 Sensors and Catalytic converter best brand and price

I am in need of getting this check engine light fixed and the tests show it is either the cats or the O2 sensors! after searching ebay and the umpteen models they have, which
brand is best to get in both O2 sensors and the whole catylitic converter setup? While I am here, which way is best to lift the truck up some that will not cost an arm and two legs as it seems a bit low to me. If I put bigger tires on will that raise the truck up? What is a leveling kit? Sorry for all the questions, but am learning as I go. Also anyone in the Lawrenceville GA area know of a decently priced shop to get it painted?

Thank you all

SuMcD