if your after mandrel bends etc, then inmy experience its nigh on impossible to get better quality or value than from OJZengineering
they will do custom bends, and they also supply al tube sizes, so you can sleeve it all together, far easier to assemble and weld up
I used them to buy the parts for my system and service was top notch
the 180 degree bends are very very good, I cut them through the bend, then rotate one leg, this gives you a very tidy and tight up and over tube for maybe a frame tube, or the axle etc
the sizes are far more exhaust friends compared to that ebay place, and bend for bend, they are about £3 cheaper each one, soon adds up over 5 or 10 bends
the other thing with the OJZ bends is the legs are a good length,
http://www.ojzengineering.co.uk/product_index.php?product=1