I have used cheap sunshades for my cars before. The unniversal ones you buy at a big box store will never quite fit right. They are either too tall or too narrow, and don't get down into the corners. I've found that once I unfold them once I can never get them folded up the same, and sometimes the material itself will start to flake leaving a residue on my dash. The Toyota Supra MkIV is notorious for dash dash issues. The vent area will peel up often breaking the plastic defroster vent (now discontinued), and exposing the yellow backing foam. The area around the cluster will start to warp. This doesn't happen over night, but it happens with age and sunlight exposure. After doing some research I decided to give Covercraft a try. I couldn't find any installed photos, only some random comments on the internet mentioning they fit great.
I purchased it from CarID.com as they had a simple checkout process and had the option to include a bag (really a sleeve) for the cover. They are also a sponsor for a lot of the Forums I'm on. It did take a few weeks to arrive but it fits great. It folds down into every corner. The slabs are nice and thick and easy to fold up. I can tell the cover isn't going to sag like some of the cheap ones. Here are some pics
I liked it so much I decided to buy one for my 3000gt. 3000gts have the same dash peal issue around the defroster vents. It's not as bad as the Supra, and there are more of them where finding a replacement dash isn't too difficult right now. Plus there are companies that make aftermarket aluminum defroster vents. Still this was more about keeping heat and damaging UV light out of the car. It's a black on black car so it can get hot inside.
I've decided I'm going to buy these for every car I own. I'm waiting for the next Holiday though so I can get them on sale. Here is one I got for my Subaru.