avorkinn

I have a Euro 92 RS and the previous ovner has welded in brackets for seats and safety harness, unfortunately he then also burned up the heater muffler going inside the channel. This muffler is in one part from the engine compartment to the front (aft of front wheel arc).
I plan to replace this mufflers but even before I start I can see that there can bee a problem to tread them?
Have anyone tried this before and can give me any hint?