Pk engine in a 50 special frame

Hi there,

I an currently running a PK125XL engine in a 50 special frame but I am unhappy with the exhaust system. It’s an ET3 banana exhaust and it’s such a pain to remove for working on the rear wheel. So I was hoping to change to a traditional exhaust that leaves the rear wheel exposed. Problem is do I use a pk suitable exhaust or a 50 special suitable exhaust?

many thanks