I had 650RWHP with the paxton on the Mamba and did feel the difference even after the belangers/HF cats,Mopar PCM,K&N air filter on the ACR ( paxton really torques after 3,000RPM )... but have not explored the upper limits of the ACR (still not broke-in). Last week someone posted that they sent the heads to Arrow for porting with the expectation of additional 20-25HP . Believe FiskeGTS a member of the FLVC mentioned that he dyno'ed at or around 600RWHP with the setup you are getting.......you might consider adding the new K&N air filter and smooth tubes to your install list....