Custom Exhaust on 84' Nighthawk

[pvo22]

I was wondering if anyone has any experience making custom pipes. I have an 84' Nighthawk 700. I can't find any 4-1 pipes. So I am planning on making my own 4-1 system. I bought a Supertrapp superlight stainless 19" universal muffler that will clamp on to the end of the header. The individual pipes are 1.5" in diameter. I want to combine them all into a 2" pipe and then put my muffler over that. Does anyone see any problems with this or know where to get the 4-1 system so I don't have to spend the time making my own. Also my Supertrapp has removable discs so that I can adjust sound and power.