[Mark Yacavone]

Only problem I ever had was where the coil wire passed through.If the grommet wasn't big enough, the wire would blacken at the firewall, like the voltage was leaking to ground.
I've had problems with coils overheating and slowing the car down, but not be readily discernible .
On a Chevy or Pontiac with rear distributor, I like the coil to be inside and away from the heat from the engine, converter, and headers.
On a front distributor like a Buick ,I was afraid the coil wire would be too long and hard to keep isolated, so I would mount the coil right up front where it will catch air from the fan or grill.