Try recalibrating your pedal position sensor.

A proper tune (especially one from Marty Ochs of MO's Speed Shop) will eliminate almost all of the lag.
Further reductions can be attained by swapping in a larger throttle body.

Trying to revert to a cable throttle would cause more issues and be more work than provide any benefit. There's a reason no one has actually done it, though many people have looked into it (and ultimately decided against it).
David Hensley
Member of Northwest Panthers Car Club

2008 P71, Norsea Blue SAP
-Message Center cluster retrofit
-Towncar Signature L heated power seats
-Long overhead console
-Compustar remote start/security