We believe in 100% PnP ECUs. There are a few steps helping to make an amazing Pnp ECU:

1. have a proven breakout board in order to confirm connector availability and footprint.
1. have a wired PnP prototype, i.e. one of rusEFI universal ECUs with harness adapter and breakout board connector. Depends on #1
1. investigate cheap compatible used ECU cases, if applicable.

Once we have #2 and #3 we can make a nice PnP which uses some OEM box without the breakout board.