suggestions for upgrades one 5.0

I would keep stock tb, run 3.73's or 4.10's (4.10's if me, DONT FEAR THE GEAR), 255lph Fuel Pump, and If Wet Kit 19lb Injectors be fine but for sure safeness get 24lb Injectors if you want to.

What Transmission You have? T5, AOD?

My first modification to any Foxbody is subframes. Then gears. UCA's, LCA's, drive shaft, springs and Bilsteins. But thats me. Seems to make any engine mods much more apparent and useable.

Back in high school I had a buddy that had a 91 GT. He put aluminum underdrive pulleys, march ram air, a 65mm throttle body, and 3.73's in it, as well as headers, off road H and a cat-back and it ran pretty good.

Well what are your plans and budget?

At your point there are so many places to go it's not funny. First of all, your car has plenty of power to go pretty fast, but it's making that power where you can use it is the thing. You can get a 400rwhp fox into the 10's, but just because you have a 400rwhp fox doesn't mean you are going to be able to runs 10's, you might not even break into the 11's. You have to be able to get that power to the ground and a stock foxbody already is about overpowered for it's suspension. The rear suspension on the fox is horrid and after all these years the rubber is probally not near up to spec and IMO it's borderline dangerous. It's a good 4 link setup, but those stock UCAs and LCAs are not what you want. Not only will it hook much better but the car will feel so much more secure even under normal driving and much better when cornering.

I'd start at the back and work my way up. Gears and rebuilt tracton loc, UCA/LCA, subframes for beginners.