I will second Unleashed Tuning, Torrie is very helpful and knows his stuff. I only mentioned the octane learning because it would be great since it is primarily my wife's DD, but she knows to run nothing less than 93, and if not available I can walk her through flashing the 89 tune.
As for the pedal question:
if you are referencing the "Pedal Commander" or similar OBD plug in devices, hard pass on that. I would not recommend. Any tuner (Unleashed, Livernois) will be the way to go using a proper SCT, BDX etc tuning device is really the only way to go.
Unleashed will upgrade the transmission shifting which is a HUGE improvement on it's own.
I wouldn't mess with the cats, unless you are racing and need every bit of edge (pun intended), but that would go with big turbo's , full exhaust and fuel system upgrades to say the least.