Scoutsout Rexxy's is an ST - with a daytona motor.
RS's have the half fairing and are more of a (cosmetically) budget model compared to the ST - instruments, fairings, blinkers.
Mine has the only belly pan (that I am aware of) available for the RS (Triumph part).
and the pan itself.
The supporting brackets are very purpose built and make it easy to fit but I wouldn't pay the $500 that Triumph ask!!
The belly pans from the 99-01 and the Speed Triples are all interchangable but the hardware is very different. The main difference in the belly pan itself is the cutout as Rexxy said.
There are a few slip ons. The Triumph Carbon Can (TOR) is a good choice but there are Arrows, 2Bros and Staintune that do some excellet aftermarket pipes for the RS. The ST's aren't interchangable (except for the 04 RS model).
Good luck.