Ok, i am looking at both the RS and TS. I am only worried about the performance aspect of it, so here is what i am stuck up on:
It says the RS is wider and also has a wider track. My guess about the wider track is the wider tires, but what about the over all dimensions of the car? It also says it has a sport tuned suspension. How does this differ from the TS other than the tires and wheels? Are there any other performance related differences other than weight?

When you say TS are you talking about the USA TS Wagon only or Canadian TS wagon and sedan?

2004 model.

The TS and RS Sedan have the same dimensions. Only differences are:

black leather wrapped gear selector, parking brake and steering wheel on the RS. Soft grip plastic on the TS.

Spoiler: Low profile type with integrated brake light is standard on the RS optional on the TS.

Fog lights: Projector beam halogen is standard on the RS optional on the TS.

Some kind of clutch difference.

Floor mats: ""2.5RS"" embroidered instead of saying "Impreza".

Interior: RS style off-black flat woven patterned upholstery instead of the TS Interior: Light grey flat woven upholstery.

in Canada, if the website is right, they have the same wheels and tires.

Makes me wonder what makes it worth the price difference?

if your talking about the TS Wagon, the wagons are all a little bit narrower.

i am in NJ, so it is the TS wagon and the RS sedan. Though now it is the RS wagon and RS sedan. Is the TS wagon the same as the new RS wagon? And the new RS sedan is now 18k, same as the wagon. Why is it cheaper?