[SprintST]

I believe the RS went to a single sided swingarm in it's last year because Triumph didn't want to make a last run of dual sided swingarms just for it, as the 955 Daytonas were also going back to single sided at the time. Thereby making the LE(Last Edition) RS an ST with just enough RS parts on it to make it an RS.

The advantages of SSSA are:
1) Chain adjustment is much easier
2) With less swingarm moving around you can tuck the bags a little closer into the bike.
3) It looks cooler :-D

SSSA are also marginally heavier and slightly less rigid as dual sided. But these things are really only noticable at true race speeds. Most of us mere mortals will not notice these things.

 

[SprintST]

I forgot to mention the quicker tire change benifit. Then again, you do have to have a MASSIVE socket and torque wrench to do it with. So some argue it's not that much more convienent, LOL

 

[SprintST]

So will the headers and full exhaust setup off a single side swingarm setup work with a double side swing arm? Will 2000 st or 2003 rs exhaust system work on 2000 sprint rs?

I don't believe the full exhaust for a SSSA will work with the 2000-2003 RS that has a double side swingarm. The SSSA header will probably conflict with the right side of the double swingarm. But, all those year RS exhaust should work with each other.