If you are using an anti-scuffing paste make sure that there is no "carbon content" as carbon can cause corrosion with aluminium.

Tails 1990 928S4 Auto.

 

Yea, with the right tools it is almost never a problem.
BTW, all the pro tools for plugs are pretty much all 3/8ths drive.

While Snap-On makes many spark plug tools, got pretty much all of them, the one I use on the 4 valve 928's is a very deep spark plug socket, still need a short extension, but at least if the extension comes off you can get the socket out with a pair of needle nose if you have to.

 

My favorite plug tool for the 928 is a no-longer-available H-F piece that has the plug socket captive on the end of a 3/8 square extension. Only one cylinder is a challenge with it, and only because the crossbar is directly over the plug well. The captive swivel connection means that the socket can't be left in the well. I bought the tool many years ago for a boat I had at the time, but it turned out to be the perfect fit for this engine. The socket itself is a slip-fit into the cam cover wells o no change of getting a plug in wrong. Easy place to use the torque wrench too, something the toolkit piece doesn't support.