Mods- sorry if this is in the wrong place!

I have an 88 E30 325 (not "e", not "i"- NOTHING).

It (I assume) gets classed with the other 325 "e"/eta cars, because that is the motor that is in it. Seems easy enough.

Now, if I swap just the TOP of an "i" onto the "e" bottom end, I don't change anything about the displacement, but I do increase airflow on the intake side.

Where do I end up being classed? My thought is Tuner 3 or 4. My "base" car is the 325e, while I don't have a motor swap, so the logic of swapped motors moving you to the class of the origin car does not seem to fit. The motor is not really built, and even the head is the same on my 88 as it is on the "i" cars.

I am basically swapping in intake, throttle body, and other intake-related parts. It falls somewhere beyond the "Cold Air Intakes (Before Air Flow Meter) Permitted" of Tuner, but does not really change engine internals- just peripherials.

Help?