I have a full bolt on 5.0 and I wouldn't expect to hang with an RS3. What do RS3's dyno at anyway with that stock tune?
On the stock Roush tuning we usually see between 420-460whp actually.
They updated the tuning at some point so that's why there is such a large swing in the power they make. Their calibration is so weak that we are able to see gain of around 100whp with just our tuning alone.