And if you did, what did you do to protect things like the shift bushings and the wiring harness?

The coating won't hurt the wiring, just cover it. You can remove the shifter, rod and bushings. My guess is your bushing should be replaced any way. Just keep it away from the throttle and clutch tube ends. You don't want it in there or on the cables.

yes I've used it in many areas, but my car is a bare metal chassis. It works really well to snake into those areas I cannot reach with paint

I also used it on a bare chassis. If you have the engine out you can access some spots in the shift tunnel thru the engine bay that are hard to otherwise. I used Eastwoods rust converter first then followed up with the frame coating. It is very thin and does seem to get into all those nooks and crannies.

Andrew

I use it. Flows very well and stays fluid long enough to creep into pinch flanges and seams.

Me too and I also recommending pulling everything out of the tunnel

with all of the above. I used it in the center tunnel while the drive train was out ... will eventually get around to the longs before new carpet goes in.