3.8L 2004 Ford Mustang modifications?

I have a 04 Mustang Convertible with the 3.8L V6 and automatic tranny. The car is in excellent shape and has only 49,000 miles on the motor. She's slow as snot though.

What is the best way to give this vehicle GT performance without selling the vehicle? It was an unexpected gift and very sentimental to me.

Was thinking of a Cold Air intake, high flow headers, and a true duel exhaust with high flow cat's. Does anybody have a link or first hand experience if this is worth the time and money thrown into it?

Had the car for 5 years now, been beat by to many Civics off the line lol.

Added (1). Meant Selling the Vehicle and buying a GT Sorry.

"What is the best way to give this vehicle GT performance without selling the vehicle? It was an unexpected gift and very sentimental to me. "

You're going to have to spend a grand or two on forged internals (rods, pistons, and crankshaft), and another $4k-5k for a supercharger. That will get you performance that slightly exceeds that of a stock GT. Bolt-ons aren't going to come close to getting you there.

The other guys have it. I don't see an engine swap mentioned though, I would assume a later/better V8 could be swapped in the car? Let the Ford guys answer that, but NORMALLY if the engine was used in other vehicles the same year of yours (like V8 Mustangs) then they will fit in your car. I understand the sentimentality, finding a wrecked V8 mustang as a donor shouldn't be too hard, but you'll need/want the whole thing as you'll need a TON of parts. Couple thousand should get you the donor IMO.