1. The Targa top, sometimes called the skin, that you buy from the dealer or any of the after market suppliers, is a vinyl piece that comes cut and sewn to fit. The front and rear edges have the binding, or beading, sewn in place. Similarly, the headliner comes cut to fit and it's edges are sewn and bound. There appear to be two kinds of vinyl that most places use, the domestic vinyl made by Haartz, and the German vinyl. The former has a coarser pattern and is shinier than the latter. I used the former; it's cheaper. I also think it looks pretty good.
2. The top comes apart easily. Just unscrew the rubber window seals on either side, and then the rain gutters. You'll also have to remove two metal trim pieces on the frame, and perhaps fold back some of the vinyl trim on the frame. It'll be obvious. In my case, the top was cut away from the hold-down clips, but the headliner was beneath them. So if you're just doing the top, maybe you can leave the clips in place. If you're doing everything, and I'd suggest you do, since the headliner is cheap enough and you might as well as long as everything's apart, then take off the clips too. Then start ripping off the top, and headliner, BUT pay attention to how things were put together, and save the top so you can look at it if you need to during reassembly.
3. The top consists of three aluminum plates that are held together and to the front and back ends by burlap and webbing. The webbing appears to be the strength member. Actually, webbing might be the wrong word. It's simply two pieces of tough stuff, a few inches wide, that run down both sides of the top, front to back. I think the burlap is there simply to prevent the vinyl top from chaffing on the aluminum. The webbing runs on the top side. It's not woven between the plates.
4. You can take apart the rest of the frame if you wish, but it probably isn't necessary. If you do, and you're not acquainted with auto trim techniques, you'll want to know that the plastic buttons have a pin in the center. The button is removed by driving the pin (use a nail, the head side on the pin, not the point) through the button. This releases the button's catch mechanism.
5. The webbing on my top was held to the three plates and to the front and back sections with rivets and glue. I replaced it with seatbelt material, available from almost any fabric store. I used pop- rivets, 1/8" dia x 1/8" long. This is one of only two places that I'd offer advice, although you don't have to be a genius to figure out a procedure for yourself. It really isn't very complicated in spite of the popular wisdom which says you shouldn't touch a Targa top unless you're a professional. The plate spacing is determined by the webbing, and this in turn sets the entire top geometry. To get it right, I put the clips back on the plates and aligned them with the unfolded frame, and then tightened them. The top is now fully unfolded, as it would be on the car. Everything is in the right place. THEN I put on the webbing. I also then put on the burlap, gluing it to the three plates and to the end pieces. I didn't actually use burlap because the burlap at the fabric store was too weak. Instead, I used a scrap piece of fairly tough material. I don't know what it was, muslin maybe. It came off the odds and ends table. 50 cents.
6. Now when you fold the frame you can be certain that when it is unfolded everything will be in the right place.
7. You'll have to remove the clips at this point, since they will go over the headliner (for appearance). But...you want to be sure that they can be put back in exactly the same place. I simply held the clip 'nuts' in place by gluing a piece of foam rubber over them and to the aluminum plates. That's what it looked like had been done at the factory. The reason 'nuts' is in parenthesis is that there is a single 'nut' for both bolts in each clip. You'll see what I mean when you do it. But after thinking about it I decided it would have been much easier to just hold them in place with a piece of duct tape. All this will be much more obvious when you actually see it.
8. Put the top on, cutting away here and there as needed to fit the frame. Again, obvious. Glue it down along the flap that folds under all around. You're gluing only the flap, and you're gluing it to the underside of the top(the inside of the car side, so to speak). I started gluing from the center (of the front and back) outwards towards the sides, so I could smooth it nicely, but I think it would have gone as well had I started at either end.
9. The raingutters go on easily.
10. The headliner is simple. Just put it on, it fits like a glove. Use a little glue to hold it to the top. You'll have to stretch it a bit to get it under the clips, and you'll have to poke holes in it to get the clip bolts through. Again, pretty obvious when you do it.
11. Voila. New top!