2.4 Drone-

My 1995 (bought in Feb) has a pronounced drone between 75-80 mph, which is pretty common interstate speed.
It’s a 2.4 2wd, with what I believe is an old stock exhaust (rather rusty).

I’m thinking it’s the exhaust, as 4 bangers, esp. 1990s ones, are known to commonly have drones/resonance that only lasts loudly for 5mph, then dissipated above & below that.
My 1990 Miata had a bad one before the current exhaust (Racing Beat- has one, but not real noticeable).

I assumed this is a normal exhaust issue, but am unable to find info on here.

My plan was to get the LCE header, as header cracks are a known issue. Would that help?

My mod/fix sequence has been going down the list.
Tires/rims are next. The tires mow are hard rubber crap.

Then, look at exhaust/intake-to get good engine breathing (may not need much).
Probably new cat (keep setting off o2 code when low RPM driving)

Then, look into suspension/shocks, etc.