I have a 1997 E36 Coupe. I don't think I've had an overheat warning with this install yet. I did with my Integra a couple of times in the summer though.

What settings do you keep on your climate control? I tend to leave mine set on Auto - though at first I used to pick where the heat should exhaust from.

If I want to kick the temperature up very high I'll usually direct the heat to the foot wells and the windshield. This means there's either very little or no heat coming from the center console vents.

The space the sled fits into in the dash is stock apart from having removed some plastic from the very back depths (for better wire routing).

Bruno