17.1.4.D.1.a.6. Fuel injected cars may alter or replace the engine
management computer, or ECU, provided that all
modifications are done within the original OEM ECU
housing. Only the stock (unmodified) OEM ECU
connection to the wiring harness may be used. The
allowance to modify the ECU in no way permits the
addition of wiring, sensors, or piggybacked computers
outside of the OEM ECU housing. The stock (unmodified)
wiring harness must be used. The installation of a
resistor is allowed between the sensor and the OEM
wiring harness. Adjustable fuel pressure regulators are
permitted.

I assume the resistor can be adjustable. Can the adjustment be within reach of the driver? I don't see why not, but this would require some wires running into the passenger compartment.