What is the best way to mount an ECU in a race car?

I am building a spaceframed special (convertible) for road, hillclimb and track days and would like some advice on mounting the ECU (A Weber Alpha unit). I wish to ensure long reliable operation and protection from vibration and rain.

Space is tight and the ECU will have to be in the passenger compartment. There is no space under the seats.

My initial ideas are to mount it in a sealed box on small rubber bobbins, Or actually mount the box on rubber bobbins.

However during filming for a recent TV program I took part in, the sound and film engineers had all there equipment surrounded by foam in boxes.

What method do you all recommend?

Thank you

John