Butyl is what the industry uses, and it's not that expensive. However, even if the rear window was glass I would still not recommend using Silicone, as it's adherence to the composite hard top is questionable. I only use Silicone to fix plastic to glass if it is not structural. More Pictures of my car with the top can be found at Group A Toyota MR2 Spyder Hardtop | Group A MotoringīTW, as an aquarium hobbiest/builder while Silicone has tenacious adhering ability to glass, it's 'stick' to plastics (plexi/lexan.) is less than 50% of that to glass, and even then it's hit and miss. Overall, great fit, very light, and relatively inexpensive. The company is based in California, so if you live in NY, it will take a lot longer to arrive. One of the only complications I see is that they can only ship it to a commercial address, so be wary of that. They are made to order and take quite a while to ship. It will reek of resin on the inside of your cabin for while, just FYI. Seals are included, but the OEM ones off your soft top will fit perfectly so use those. Not for the faint of heart, drilling and measuring is required for that step. A preshaped lexan rear window is provided, you supply your own bolts and caulking to adhere it. Also, it costs LESS than OEM! The construction and finish is fantastic, and I had no fitment issues whatsoever. There is a fiberglass option as well, but I opted for the cf for the looks and weight savings. As the title suggests, I wanted to make a quick review of the GrA cf top.

Mr2 spyder hardtop full