slip on question

So i have a couple yoshi slipon from sportbikes i want to use for the exhaust..my question is..the exhaust flange on the cat is the offroad bll..donut style on the cat,,how does one install with out cutting the stock pipe ..is there an adapter that i can use to insert into the yoshi to get it to pair up with the springs?
thankyou!

i tried the search feature on forum to no avail..