I've gone to the darkside(bought a ford)

I had a '94 Hyundai Excel 5spd manual, 4 banger 4 door. I added a Jacobs Pro Street Ignition and went to 40 mpg on the Hwy. No other mod was made.

Given the year of the car, it is hard to improve the ignition. IDK if a ignition add on will help. The Hyundai had a distributor, the Taurus does not.

On my '99 Taurus, I added a K&N into the stock box and a Accel coil. The result was only really seen on the Hwy. to the tune of about an extra 2-3 mpg at best.

I'd like to try a cold air induction pipe and a smoothed out pipe.

On your car, or any other mod to my Ford, would be the muffler. Tricky though since the wife doesn't want a muffler swap alone. Reminds her of the "Fart Can" crew and she wants to avoid that in a big way along with the drone issue of aftermarket mufflers. I do not blame her.
I was thinking about it though. It is a single exhaust pipe Taurus. IDK if a dual would help much at all. Well, at least in stock configuration. Perhaps "Super Trapps" would be OK.
Being a single exhaust car, there could be a 02 sensor issue in true dual's. IDK if the dual exhaust Taurus cars are true dual. Which could very well have extra 02 sensors.

Looking forward to your tinkering and I have a good feeling on this outcome for a few MPG's. Sub-scribed!