So far ive made a sidepipe that ran to thr front of the back tire, then exited, and now im redoing it to a stack. Pro's about the sidepipe: quiet, you didn't hear it as much. easy to work around, had a nice tone. con's about the sidepipe: lowest hanging thing on the tractor so if I bottom out that's the first thing to hit. my front tire hit it to when I was steering sharp.
Pro's about stacks: sounds good, loud, no low hanging issues and easy to make con's about stacks: if you weld it right to the original pipe that comes out of the exhaust port and roll, you can actually crack the exhaust port, making the whole engine block junk. The stack might be to loud because the sound is in your face all the time.
Another stack drawback- rain. IF I were to build a stack, I'd put a flapper on there to keep rain from going in there, and then running into the exhaust port. Obviously not much of a concern if you leave it parked in a sheltered area.
Have been considering this too there is lots of videos on You tube I have been watching but haven't took the plunge. The hardest bit is going to be to get the old exhaust of as it has two seized bolts I haven't run it up to temperature yet to see if the come undone with the heat from the engine. I have seen somewhere someone making a plate that you can bolt on . I would recommend a glass pack. I have seen a guy on Youtube make one of these out of two oil filter cases . Looked neet but wobbled a lot