hey guys i just ordered a carsound catalytic converter off ebay. no i want to get flanges welded on to make the cat a bolt in process. can i use the stock flanges off of my stock cat? or do i have to buy flanges? do you think a muffler shop will have the right flanges? i want to get the 2.5" but i can still get the 2.25" if it will make welding the flanges easier. some one help please. thanks.