No idea how old you are, but from someone who’s done it, straight pipes are honestly pretty miserable to deal with. They’re incredibly loud, drone at cruising speeds, and will get you pulled over by the police in most jurisdictions.
With a 5.0 fox, the world is your oyster when it comes to street-legal exhaust systems, some of which are still obscenely loud. Bolt-on and highly interchangeable parts and kits are available from headers to tailpipes, from every manufacturer you can imagine from Flowmaster to Magnaflow and everyone else in between.
My last fox (granted, I sold it in 2006, so it’s been awhile), had Flowtech shorty headers, a MAC off-road H-pipe (you can pick up a lot of “loud” right there if you want, off-road H-pipes aren’t strictly legal, but since most areas aren’t enforcing catalytic converter requirements on 24+ year old cars, it’s not usually a big deal), and the Flowtech Warlock Stinger cat-back system. Off-idle it set off every car alarm within 100 feet, and at wide-open throttle it roared, but everywhere else in between it was nice and pleasant.
My last four Mustangs (two Mustang IIs and two 4.6L S197s) had different exhausts on each.
My ’76 Mustang II had Blackjack longtube headers into 2.5″ pipes with Flowmaster Super 44s with dumps at the axle (it sounded amazing, but was so loud you couldn’t hear yourself think, much less carry on a conversation, in the car).
My 2010 GT had Pypes Pype Bombs axle-backs on it, and was bone-stock from there forward, and sounding very aggressive, but not loud enough to get me pulled over.
My ’75 Mustang II has Heddman longtubes into a 2.5″ H-pipe, and had Flowmaster 40s with dumps until I cut them off and replaced them with Dynomax Super Turbos…