I ran a 3071 .63 on an OEM hybrid w/ wrx cams. I made well over 400whp with enginuity as a base flash, and then UTEC for tuning.
SPEND THE MONEY ON LARGER CAMS. 264 or bigger if you are staying with non-AVCS heads.
Head work isn't a neccessity, just use the proper springs to support your desired rev limit. Also, fork over the $300 for shimless buckets if your '03 doesn't have them.
Don't bother running 2.0 cams and a 2.5 engine if you hope to make more than 350whp by redline. "Peak horsepower" will never be a a gauge on how "fast" a car is.