197 de-cat and RS tuner

[Luke_m]

Does anyone know of anywhere that sells de-cats for the standard 197 exhaust system? I've seen a couple of videos of people with the standard system with a de-cat, but no where i've looked seems to sell them.

Also could anyone exoplain to me what the RStuner is, i keep seeing people mention it on here but not what it does and where you can get them from.

Thanks