I just finally finished up a v3.0 for my car. My original plans were to isolate the tach input to another board to help isolate noise within the v3.0 board. I have always had 2 theories on this issue:

V3.0 board has a flaw or is more succeptible to noise,
Cars with tach noise have issues witht he sensors degrading and the v3.0 can pick it up.

I built the v3.0 in its factory design (sort to speak) and set it up to run just like the v2.2. Not a single spike!

Here is my setup
V3.0 running tandem with Factory ECU
Spark "pullup output" to Crane Ignition box
NO IAC
Idle 800-900
Factory crank receives power and ground from the factory ECU
Factory TPS " " " " " " " "
NO SPIKES


no special noise supression wiring only GXL harnesses i sell routed with factory harnesses.

I will drive this thing a bit more this fall to see if conditions change.