I think many don't want to go two sizes smaller unless they have to. I think many, including me, are looking for the best balance of power and driveability. If my engine is down 5-10hp, but it is better on the street, I'll take it.
I would run what You have, run valvesprings that can accommodate .625" lift, get this package optimized 1st... I think it will be very close to what You're looking for.
