I have the HKS EIDS for sale. It’s for an SR20DET but can be used with an RB, KA and quite a few other engines from Nissan. The settings have been set and tuned for an SR20DET though.
"The HKS Electronic Idle Stabilizer (EIDS) smooths the signal from the MAS when running blow-off valves that are vented to atmosphere (non-recirculation). This helps avoid rapid changes in metering that can cause idle stability issues. "