Might it be possible to take the exhaust system, just the y and mufflers, off a 2003 SLE and put it on a 1999 SLE?

The newer Bons use the same exhaust as the GTP. I know the GTP exhuast won't cross over to a 92-99. HOWEVER.....you're only talking about the back end......Hector? You've been working on this.

Yes..just the back end, where it y'* out from the single pipe. I'm thinking there may be enough room under there for the Y-Out portion of the 2003 exhaust.

Here is my thought, odds are because it is still a Bonneville, the back end will be the same most likely with the same mounting points. But the middle section of the 92-99 and 2000+ Bonneville'* are sooo different. The only way to know is to try and it'* just pipe. A wrecking yard will give it to you cheap since noone else is going to want it anyways.