Buddy and I are trying to figure this out. IF we take off the ST baffles we will have the normal two holes for through hull exhaust. At that point put 4in tips on it or whatever size they are. So at this point we would be at a thru hull exhaust loud all the time.

What about getting silent choice on it Because it doesnt have a Y pipe for exhaust to be diverted through the prop. Is there some solenoid that controls noise a little but still lets water and exhaust out. Or could you just add a Y pipe and get a normal corsa diverter and the exhause comes out like that.

you will need to pull out engine/s to get y pipes in..

isnt there a diverter you can use so you dont need to do the Y pipe and just go straight out the back,

The diverter either dumps the exhaust into the Y pipe or out the back. So you will need the Y-pipe installed and then the diverters installed. It is much cheaper to put on full time mufflers out the back unless you just have to have wide open exhaust.

you will need a Y pipe and diverters.
in the picture you can see the diverters turning down to the y pipe