I'd stick with the Ford racing stock intake. You could go eddy intake. But there's more to it than you think. Just ask Keeney. The stock stuff will support a lot of power.
2003 GT: JLT CAI, summit 75mm TB, C&L plenum, 24# injectors, Mac Prochamber, SLP LM1 cat back, 3.73 Gears, FR500 Diff, FR500 diff cover, Jmod trans and shift kit, Max Motorsports subframes, Koni oranges front and rear, DBA discs front and rear, shrader performance rear seat delete, APSX D2 wideband, MPT happy customer.