The CFI manifold, I think you'll find, will not allow enough air through the motor to make extractors/cam anything like as effective as the MPFI setup would be.
As for hearing there is hardly any difference between CFI and MPFI.....MPFI will give you at least 10rwkw all by itself! And it's really not hard, simply bolt off, bolt on, and modify 1 wire, in the manual version.
Proud TQE Operator and President of SEFAG - the Society for the Elimination of Ford Automatic Gearboxes
Pacemaker headers + 2.5" exhaust
EF Fairmont interior
Lowered King springs
5 speed manual
Newest mod: EF Ghia wiring loom and dash