You are not getting any replies to your question. So here goes. I did not do it but had it done two years ago. Thus just a few brief comments. The unit is welded to the seat frame after some careful measurements provided with the kit. Pretty straight-forward.
The upper surface of the seat cover has to be cut to accept the up-and-down square adjustment shaft. But the rectangular chrome trim covers that nicely.
A local automotive glass/upholstery shop. The cost was $350CDN, about $325US at that time. That was cleaning the seat frames, primer, and rustoleum paint. New foams, seat covers, nuts and bolts, hockey sticks, plus the head rests. Parts were my cost. I only quoted labour.
I installed my brackets myself only becuase I was a certified welder in a past life and have the equipment in was garage.
The welds that were requirede arent that big and I was able to keep the heat under control.
But I can tell you that I was able to made the modification w/out removing my seat covers.
Bought my sets from corvette central.
Good luck... Jim