would a K&N and some cats be not enough?

[withamc]

My first mods were shorty headers, 2-1/2" H-pipe with cats, 2-1/2" Flowmaster cat-back system, I took the silencer off the air cleaner and advanced the timing to 14. Big seat-of-the-pants difference. Before, the engine pretty much cut out at 5000 RPM. First time I punched it after the mods it zipped right to 6000.

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86 GT, GT40P heads, Cobra cam, 1.7 RR's, Cobra intake, 65mm TB, 73mm Vortech, 24# injectors, 2-1/2" BBK H-pipe (w/cats), Flowmasters, 3.55s.