What kind of driving do you do? Drag racing? Autocrossing? You just wanting a lower ride? You have to be specific on this to help determine what suspension manufacturer you want to use.
For OEM replacements you can't go wrong with either Monroe or Gabriel shocks and struts. Advance Auto Parts & Autozone carry them. There will be several choices for both the front and rear shocks / struts. Go with whatever you or your wallet feel comfortable spending. They have a lifetime warranty as long as you keep your receipt (copy it as the laser paper fades). Stay away from KYB stuff both stores sell. They are no better than OEM and are way overpriced. I've owned a few Foxbody Mustangs. For ones I've drag raced I've used rear shocks meant for a four cylinder Mustangs and four cylinder rear springs for best weight transfer and squatting. The front used OEM V8 struts with four cylinder front springs. Lots of younger newer guys in the hobby go spending big money on expensive suspension stuff when with this set-up is old school tried and proven to work.