wierd, the differnce between a renix vs a HO flywheel is how the teeth are read, with the renix having more pulses per rev and lookign for missing pulses, while an HO only reads 4 pulses, both are made of iron and a CPS reacts to anything that is made of iron... the incompatibility you mention may be when the use a Renix flywheel with a HO cps AND a HO ecu, in this case pulses don´t match..