Josh, the answer to your question will be found on the dyno. Keep turning it up until either A) you start going lean (try adjusting the fuel computer) or B) If your air / fuel ratios are safe and you turn it up and she does not make any more power, then thats the limit of the SP57.
With a properly tuned car you should see 550 RWHP if not more. After that the fuel system gets marginal.
Lar
SP