Having noticed the various placements of electronic ignition boxes in other cars, I thought I would offer my suggestions.
On my first BMW, I mounted my Delta Mk. 10 on the right front corner of the engine compartment, near the air intake thermostat box. However, the gas fume canister on my '73 BMW eliminated that position. CD mounting instructions specify a location with cool air flow -- the passenger air intake trough, on the firewall! A tight location to drill mounting holes, but not impossible.
The CD unit, a Mk. 10B this time, is sealed fairly well, so in it went. That was over 60,000 miles ago, and I've had no problems with it -- even when the car's been covered with snow. A grommeted hole gives access to wires and seals out fumes from the engine bay.
Later installation of an Allison Breakerless system went on the shelf to the outboard side of the CD box on top of the tire inflation decal. This location also puts the electronics about as close to the coil as you can get, and yet they are shielded from the hottest side of the engine.
The Allison has been in about 30,000 miles -- no problems, no adjustments after installation, but yes, I do still carry a set of points in the trunk.
Author: Dick Carlson