ECU for Rotrex build/WTB?
 

So I'm trying to pick between 3 options for my setup. I have a 1997 Miata with A/C, power steering, and all the bits so I have a few years until I can bypass emissions. For the rotrex build I could go with new TDR fuel and timing cards to just make things simple and easy but a little expensive $700, a DIYPNP for around $500 and learn how to tune for the first time, then option number three which is an ECU from RM engineering which I've never heard of but I think uses tunerstudio and is about $300. Don't know which way to go.

I believe most of the actual experts on here would agree with me when I say an MS3 (PnP or otherwsie) is really the most sensible solution these days if you're willing to spend more than the ~speeduino range. Fuel/Timing cards are fine if you're in CA and your choices with CARB are stock ECU or the power commander shit, otherwise a standalone ECU is almost always the better solution.

That said, I'm also selling an open-box 96/97 MS3Pro PnP, so I'm admittedly biased in the matter, but there are approximately 3291850 threads on this topic, I suggest you do some additional background reading.

Do it once correctly. Megasquirt. It's really not that difficult.

If you're going to build an ecu build a MS3X. Swap the stock stuff back on for emissions testing.

https://trubokitty.com/#/

I spent $800 on an MSPNP and have no regrets at all. Tuning software is flexible and well supported, if I decide to make some radical change in future like a turbo or whatever I can easily update my tune with existing hardware.