I say look on the internet for prebent,,, aluminum likes to crack if it isn't pre heated. you can find them a lot cheaper then having someone with the right bender to do it
Mac, a mandrel bender is what your looking for, big $$$. I have heard of people using everything from sand packed inside to a mixture of wax and sugar. Musical instruments are filled with water and frozen before bending.
1.5" might be too small for an exhaust shop. But the guys are right a mandrel bender is what you are looking for. Just out of curiousity, would another metal work? You might be able to source some mandrel bent tubing from one of the exhaust companies like flowmaster or magnaflow.
Is it normal for one testicle to be larger than the other two?