There are quite a few companies selling pipe kits to design (and weld) your own exhaust. But 7th Phase Inc. is the only one I know offering a stepped pipe kit. A lot of trouble saved. Something very useful when you need to be different and/or when you need clearance in some places. Their kit includes 12 x 2 1/4" in pieces in straight, 70 and 90 degree bends in different lengths and collars. 7th Phase Inc.