I suggested SE parts beacuse as you have probably read and seen from the pictures the Inferno parts do not seem to fit as well as the SE parts. The only good looking part off the inferno apperance package is the hood. The Inferno package alone is 1,000$ add another couple hundred for paint and its already probably out of your price range. Rims + tires could add up to another 800$. I would not recommend getting part of each appearance package and frankenstiening your car together.
I think I seen a Grand prix with underbody lights and the inferno spoiler in the movie 2fast2furiousso I am not sure if you would like to go that route.
SE air damn is probably the #1 part should get. It fitts like its a stock part and it gives the car a unique look for not to much $$$. Go from there and add what you think looks good and is in your budget.