I have never tried to remove the valve covers on my 914. It looks nearly impossible w/o removing exhaust or heat exchangers. Does anyone have any suggestions or techniques as to how to do this?

I use screwdrivers to pry downward on the spring clip holding the cover in place. Be sure to pry it down so it is below the bottom of the valve cover. You may need to use the screwdriver to gently pry the cover away from the head. Then, I will slide the cover towards to back of the car until I have clearance to maneuver it around the heat exchanger.

There is a stuck cover post on here, still active that has plenty of suggestion in it.

Yes, one of the better suggestions is to wrap a rag around the bale and pull down on the rag while prying with the screw driver. Real easy after the first go.

Rag and I pry from the side. I can't get enough clearance (because of the heat exchanger) if I pry from the center.

Use a large screwdriver or prybar where the bail pivots on rear of the heads, leverage the bail out of the hole, remove it from both sides.
When replacing make sure the angle of the bail is downward, it is not symmetrical, and place both sides of the bail in their respective holes, leave it in the lowest position, install the valve cover and pry the bail up till it snaps into place.