True, Jim, the 177 did not have corrosion protection of the spar, with the exception of the Reims Cardinals built in France. In the U.S., internal corrosion protection was an option. But, they also did not have the foam applied to the lower cap as the 210 did. The Cardinal community is fully expecting we will get sucked into the AD in the future, so many owners have included visual and some eddy current inspections as part of their annual inspections. There have been some reports of corrosion in spots, but to my knowledge, no cracks or corrosion that would require a replacement. The FAA estimates that a spar replacement would cost about $43,000. That’s assuming you can even find a replacement. Last I heard, which was several years ago, Cessna quoted a 177 spar replacement at about $12,000 just for the part. Oh, and they gave no estimate on delivery time. Unless you get lucky and find a 210 being parted out, good luck in actually finding a spar.