On my car peak to peak gain was 32rwhp, and 38-39rwhp in the mid range around 4-5k rpms no change of timing, only change made in the tune was adding fuel as my tuner had to let out first pull as it went lean around 12.6:1. Let out added fuel and got it back down to 11.9:1.
Dont get hung up on the timing thing though too much, thats the purpose of mods that allow more airflow, allows you to make more power in the tune. Where on the stock setup you add more timing and dont pick up any power. Things like intake, throttle body longtubes allow you to get more flow and tune for it for optimal power gains.
You will easily pick up 30rwhp with that intake and a tune.