I am at the point that I need to upgrade my injectors and rail(s) to make much more power. I was considering upgrading secondaries to 1600s and calling it good, but I plan to keep this car forever, and I tend to get bored and fiddle. I was wondering if intentionally over sizing my primaries + secondaries and running them at lower IDC would be OK. This would give me headroom for later and I would only have to buy one set of injectors.

Just for example:
1000cc/2000cc@50% IDC = ~400whp, which is all I want for now.

If I decide to go bigger:
same@80% IDC = 600+whp

These are just numbers pulled from a calculator on rx7.com, so I'm not saying they're exact. The car is a weekend/occasional track car, so mileage and some minor drivability issues are no real problem. I plan to do a half bridge port if I ever tear down the motor, I have a loud exhaust, no AC, no cruise, soon to be no PS or ABS, so you get the idea. I did search and google this topic, so sorry if I missed it.

EDIT: I plan to run FIC or ID high impedance injectors with CJM rails if I go this route.

 

You shouldn't have issues with the ev14 based high impedance injectors you mentioned, maybe a bit of a rich idle but sounds like you are not concerned with issues like that. Not only would a setup like this let you run more power later on but would also give you the option of running e85 as long as you have the fuel pump(s) to support that kind of flow.

 

There isn't much e85 here, but that thought has crossed my mind. Thanks for the help, I didn't think it would be a problem, but I wanted to be sure.