exhaust leak at Manifold-TTI 2 1/2 " downpipe

i think first you have to figure out why its leaking, is it the pipe being bent wrong or is it the flange being to wrong size? could also be the flange being warped from to much heat while welding.

you cant add bends with a mandrelbender if you want to keep your pipes mandrelbent unless its at the end of the pipe and there is enough distance to the last bend to grip the pipe.
could also be the flange not welded on at the right angle and/or rotation.