Wouldn't touch an FSE bore washer with a barge pole in a n/a application. (They are sometimes useful for a turbo I guess).
The spec of your car sounds identical to mine, except my zorst is a magnex. This is how it came, so I can't make comparisons to standard, but I'm dead happy with the performance.
I'd be interested in what gains can be had from the chipping route as this can only possibly adjust the timing and fueling maps I would have thought. I've seen a few places offering a chipping service for the RS, so at least you wont be stuck for choice.

S