My flop-top experience is a little off-thread (I didn't do the job myself) but should be of interest.
After we had our new '98 roadster (white top) about a year I noticed a CUT developing about two inches behind the passenger-side window and two inches above the body ... in other words, right in the corner where the top bends into the hardest folds when it's down.
My first thought was the first thing that the Chevrolet service writer said: "somebody cut your top!"
But a close examination revealed that the cut was obviously FROM THE INSIDE, OUT.
Peeling back the headliner revealed a sharp-pointed trim screw which had to be the culprit.
"No problem" he says, and they order a new top from GM under warranty.
The new top arrives and the car is trundled off to the upholstery shop that does all their warranty work on both tops and upholstery. I pick up the new top at the parts counter and take it and the car to the upholstery guy myself, pointing the problem out in great detail to both the owner and guy who will do the work.
The shop owner pats me on the head, and says "trust us".
Car comes back with top looking great.
Then, a few months later, a new cut appears, in the same place as the first one, again from the inside out. Obviously, they didn't fix the core problem.
Same process. Dealer orders a SECOND new top on warranty for the same car. (I thought sure that would blow a fuze in a GM computer somewhere, but it didn't. Maybe GM is so big it'll only notice the really BIG buck items!)
This time I insisted on MY choice of outside vendor; the shop in another town about thirty miles away who has the best auto top/upholstery reputation in this part of the state. (In fact auto tops/upholstery are all they do; no sofas in his shop!) Again, same routine: I take it there myself, point out the problem out in great detail to both the owner and guy who will do the work. And wait ALL day for the car. They seem less inclined to pat me on the head and say "trust us" this time, but rather will look to find out for sure, AND FIX, whatever the damned problem is.
That's been about six months now, and so far, so good. No cuts on the THIRD top yet.
This hasn't cost ME anything yet, but instead it's cost ALL of us, as obviously GM passes on the costs of ALL this sort of chinese fire drill warranty work episodes to ALL customers.
I shouldn't be complaining ... I've got a four and a half year old car with a near-new top on it at no cost.
And I'm not really unhappy that the top getting cut the first time... that sort of thing can happen.
But I AM unhappy about whatever system (if any!) that GM has to report unsatisfactory product events. During my years in the Air Force, if you saw something that could be done better, you were STRONGLY encouraged (really, required) to submit what were called "U.R.'s" (Unsatisfactory Reports). They were submitted on ALL sorts of things, very often things that should have been to the designer of the "DUH! Why didn't WE think of that!" variety. Plain, obvious improvements. Like a pointed screw so long that it interfered with, and cut, cloth.
U.R. submitters were often rewarded in signifcant cash awards for the really good ones that saved big bucks.
As near as I can tell, G.M. has nothing to match that system of follow up on their products.
If they have a system at all.
Fred