You don't have to use stainless tube to build your own. There are many companies that sell assorted Mandrel bends. By some same size exhaust tubing locally, cut to fit and tack everything together, weld it complete when your have all the pipe fit where you want it.... I've done it on a lot of projects, some stainless some not. My only issue with the exhaust shop systems is that 99% of the shops use the cheap bender and not the mandrel bender so all your bends have the dimples... As for a store bought, bolt on Mandrel bent system, tried a couple, still had to cut and fit to get everything where I wanted it. Mine is a labor intensive method of installing exhaust, but it depends on what level of fit and finish you are trying to attain on your truck....