if its turbo.. first off you should be running way under a 12.5 AFR...
here's some help bro.
less than 10psi: 12:1 Air Fuel Ratio
up to 16psi: 11:1 Air Fuel Ratio
9.5:1 compression or less: 1 degree retard/#boost
above 9.5:1 compression at least 1.25 degrees per psi
This will help with your smog cause you wont be running too rich being your turboed.. it'll eat this gas up, not let it sit on the top of the piston and just burn black..

Also try 11.8 see where you stand should solve all your problems.. i've tuned a few b18c's, b18c1's and b16a2's with turbos all stock internals running 10psi daily and i've seen mostly all of them run perfectly around 11.1-11.8 AFR..
Also there will be tendances to where you can't fix a drop off just make it mainly run threw.. as for instance i run a skunk2 intake manifold and mostly everyone i've tuned does and they WILL EXPERINCE a lost of power between those rpms you stated.. i have it on mine, everyone does thats the chars of the manifold man.. is really nothing you can do to fix that.. my two cents if u need anymore help pm i'll be glad to send you a few maps possible walk you threw some more.