compression or flow?

I'm no expert, but you can increase airflow the engine a couple of ways. ports can flow more or if the ports can't be opened up then more duration will flow more.
More duration tends to perform better with more compression to make up for dynamic losses from later closing intake.
So if you go with better/bigger heads/intake/headers you can (theortically) make the same/more power with less duration and not be quite as crippled by the lower compression (since the IVC is sooner).
Higher compression might support more duration but then the peak power will come in later - and a streeter with 3.55 gears and a 4spd isn't going to get to tap into that as often.
It's this dynamic that would personally lead me to favor flow vs compression.