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.

BINGO! The easier it is to breath in and out the more effective the package is. I say it a lot, get the best cylinder head you can on top of your engine. This does not mean put a pro stock head on your 7.8-1 - 318!

I feel the same way for exhaust. I’m done with the 1-5/8 headers! The only worth while one is Summits w/the thick flange but it has 3 tubes under the steering linkages and IIRC, Doug’s has a 1-5/8 that’s worthy.

Otherwise, 1-3/4 @ a min!