I know how you feel- i've recently had buddyclub spec 3 (similar to ITR) cams + AEM cam gears added to my b16a along with the intake, 4-1header, race Cat and s/s system and have the same problems.
I have taken off and cleaned the whole intake manifold, throttle body, IACV, PCV and adjusted the idle which has helped with the poor idle issue, however i too still feel a slight drop off between 5.5 and 6.5 and then everything goes like you'd expect.
i, as you, thought that as long as the timing was right it would be fine until i got a tune to get the best out of my setup, but i asked buddyclub if it should be so poor and they like many other here said get it tuned so, which route you go is up to you but tune is the answer it seems. I am due to get the cams fully degreed in (like other companies such as skunk2 recommend) to ensure all timing is correct as just doing it off the belt markers isn't the best way and then tune it up.