Congrats on the base line numbers. Stock I think that maybe a little low. My numbers were about the same as yours. I've have pics of two stock dyno other than mine and the numbers were:
423rwhp 470rwtq (99 ACR)
427rwhp 469rwtq (01 ACR)
My car (01 ACR) was a bit on the low side with 411rwhp 466rwtq.
This makes me wonder what other cars dyno'd stock. What is the average.