I have the same axlebacks and CAI with a tune and tuner from American Muscle. I spent around $950 at the time, but i know the FRPP CAI is less expensive now. BTW, axlebacks dont give you any "power" , just a better sound, and these DO sound much nicer than stock.
2008 Metallic Alloy GT Convertible Premium
Show : black top| 18" bullitt polished wheels| CDC light bar and black billet replacement grilles | black/amber corner lights | GT500 rear spoiler| AH chin spoiler
Go: FRPP CAI with StangHi tunes | Kooks LT's | FR500 axle back | Steeda Sport springs | Koni STR.t struts/shocks | J&M camber plates | UMI adj. panhard bar | LCA relocation brackets | GT500 LCA's | Hurst Billet shifter | 3.73 gear | FRPP axle girdle | Baer Rotors and Pads