Engine sound has decreased slightly

I'm at 3300 miles and the deep rumble isn't as good as it used to be. Not completely sure why...it sort of decreased the same day I had my oil changed. That night I took it out for a good drive and at the end of the 70 mile trip it almost had a lawnmower sound in the first gears...really bad. I did fill the tank with 93 octane twice...not knowing the car had to be tuned for it. Does the engine need to be retuned? I've got a CAI and Diablosport on the way.

I'm still trying to learn as much about engines as fast as possible. Do they sound differently after a tune...anyone know how I can get that deep roar back?

Yah i'm getting used to it....the speed and everythting else is just the same as when I bought it. I can't wait until the JBA long-tube headers get here, that the JBA H-Pipe and Magnaflow Exhaust should change it up. Although I have to say the Stang sounds damn good stock.