Someone prove me wrong, but I'm fairly certain the ride height is not 1.5" lower. The front fascia is simply 1.5" closer to the ground is all. The springs and suspension is no different than a regular GT.
Also, it does not actually have a larger air intake manifold, but the front fascia has a larger area for air to come in.
This is off of Ford's website:
"Exterior accents include side scoops and unique front and rear fascias. The front fascia has a larger air intake and is actually 1.5-inches lower than the standard GT. The rear fascia is also cut differently with less tuck-in."
The GT/CS has absolutely no power or performance upgrades over the GT, they are all just cosmetic upgrades.
Personally though, I love the CS's bumpers and my GT is in the shop getting them installed as we speak!
Apex Stang