KarKraft is selling off the lower intakes from Pre-fix 99 Cobras. Appearently instead of fixing the old ones, Ford just installed new ones, and pretty much either just left the old ones at the dealer, or sold them off cheap to places like KarKraft. The Fix didn't replace the upper intake or hat(cover that the throttle body, EGR, ect, mount to).
The 99 Cobras don't use IMRCs and it shows. With the better port design the 99 Cobras peak at about 17 ft lbs better then the 96-98, but the 96-98 Cobras make about 20 ft lbs more under 3500 RPMs.
The hopefully soon to be released 4V FRPP intake and heads have the best of both worlds. They use the tumble port design of the 99 heads, but also use IMRCs, but high in the intake instead of just before the heads like the 96-98s do.
When you start looking at such great dinner conversation topics such as intake manifold runner harmonics, the FRPP design has an advantage.
But the 99 intake can fit the 96-98 heads, but only after some fairly serious and unpleasent modifications. But there is no real point in doing so. The designs are very similiar, the fit is just different. For serious modifications (especially with blowers) I like the 96-98 versions better. There is more potential plenum volume. Of course that is only a serious consideration when doing some major modifications.
But that's the long version. The short version is for $45 bucks for a similar design, it would be some good practice cutting, polishing, and placing runners.