I estimated on another thread $4k or so I believe, probably more. I have owned many racing seats and several Recaro recliners and seats far less nice than these like the SRD, Speeds, etc, no mounts, sliders, air bags, heaters, etc.....$800 each, parts to install around $500 for the pair, or more, over $2k for nice but nowhere near as nice as these and that is only the fronts.
I have been looking at Pole Position Recaro fixed back seats, sat in several different Sparco seats, have new very high grade seat heaters and a pair of Recaro lumbar bladders I could install. I have Recaro sliders and make my own floor mounts but would have to buy side mounts, need wider than pure race seats for more road comfort as tight seats no matter how good are not fun for long trips....it would cost me around $2000 to swap to those seats and take some addtional work on them plus work on the padding to make them fit us just right.....and never look as good as the factory seats.......
As you can see, I am considering all the angles to this and the main thing I really am concerned with is saving weight and safety as could wear a harness but technically should only do so if at least a good roll bar installed which I cannot do on this project.
AND, I would have all the airbags but seat side ones and what is the issue if ever employed????