Absolutely nothing wrong with a 6. Some have started with a v6 and eventually got a v8, and most still have their v6's and love them. They are great cars with lots of potential.
Exhaust is a great addition to your stang. You could get a single axleback, which is probably the easiest, or you can buy a y-pipe adapter kit or a true dual system from a manufacturer. Flowmaster, Pypes, Borla, JBA, Corsa etc are all great exhaust brands for the S197's.
You could also look into a GT styled takeoff kit. They are good kits that include all the dual exhaust components. If the stock mufflers aren't what you want, you can always swap in mufflers of your choice.
Here's a nice kit with an o/r x-pipe and GT takeoff mufflers.
Mustang_V6_Exhaust_Conversion_KIT | New Take Off
12 Black GT500 SVT PP l VMP TVS l JLT123 l O/R X l 28x11.50Rx15 M/T Street R's l BMR Suspension l Recaros
03 Sonic Blue 3.8 / 17 Magnetic Fusion Sport 2.7 EB