It will all depend on how serious you are and how deep are your pockets.
So my advice or recommendations come from personal experience and many years of tinkering.
1 A remap will or should give a little more go depending on the skill of the tuner as factory maps are a bit on the conservative side as they want reliability and lifespan /durability and little if no warranty claims.
2 Cone filters will look good or add bling in the engine bay BUT they will get HOT air flow and lose power BUT may sound better or more powerful.
3 Straight thru exhaust with a larger diameter pipes should add a couple of HP.
Now if you really want to get serious about getting more go from a NA car here we go and you have won Lotto.
1 build a larger / over bored balanced bottom end with FORGED rods and higher compression pistons as they will be considerably lighter so it will be more responsive.
2 lighten the crank by knife edging it as well as polishing it.
3 port and polish the head and install larger valves
4 upgrade the cams.
5 Fit a well designed set of headers.
6 wire in a tuneable aftermarket EMS / computer IF the factory unit won't allow remapping
7 Fit a lightweight flywheel.
8 fit lighter forged alloy wheels.
9 Fit lighter brake discs and callipers.
10 Find a dyno tuner who know his stuff and won't remap it so it is right on the borderline of detonation if you want it to last.
FYI I have done all of the above except the crank knife edging BUT have had a stroker crank in 1 of my motors in my previous mainly track car.
