I am looking for loud which my stock debaffled gives me and I love it. What I hate is the loss of torque. Will my FP3 give me back that power or will the aftermarket set be the better option. Sorry to sound like a broken record!
The newer FP3 (last 6 to 8 years) is a "flash" tuner, in contrast to the older FP3, which was a "piggyback" tuner. Flash means it puts a new fuel map into the ECM; piggyback means it just makes add-on changes to the original fuel map. All of the modern tuners, such as TTS, PowerVision, FP3, and Direct Link are flash. In general, they can change more/most of the engine parameters. The older tuners, like PowerCommander III and V, or old FP3, are piggyback, and less capable.
Be aware: the use of most flash tuners voids your factory warranty or ESP. This is much debated on here.
Your exhaust system choice is on a scale running from Circuit-track [extremely loud, with best high-RPM HP, but loss of low-end torque (TQ)], to Stoplight-to-stoplight [not so loud, but best low-end TQ, good acceleration and drivability, some loss of high-RPM HP]. It's the baffles, cats, and smaller diameter that quiet the system and keep the TQ.
Lots of people go through a long trial and error period to find the best balance of loudness and performance...and there's no tuner (person or equipment) that can overcome the laws of physics.
It's essentially impossible to get the loudest sound yet keep the low-end TQ. The closest you can get is what fastfreddy said about a 2 into 1 exhaust setup. I don't have any recent experience with them, but people on here seem to have the best results with a Drago or D&D 2-1 system.
As far as the best tuner equipment: get the best tuner
person within the area you're willing to travel...then use the tune box they prefer. It's way more about the person. You can get recommendations by searching or by asking on here. Good luck.