When I worked at Midas I made a 3 inch down pipe off the bend card they had for the stock down pipe. I welded a flared 2 1/2 end on it and it worked great. I threw it out when I put the hooker 2 1/2 down pipe on it. I should have kept it. Im sure Midas still has bend card for the down pipe. Real easy to make with that card and the bender. They dont even use benders that much anymore .I used it all the time back in the day.
My bad didnt see Hot air section. Midas had cards for those too. A good exhaust guy could make that