T-tops - If there are not any for sale here, Thirdgen.org had a pretty good sized For Sale area, and there are usually a couple of members parting cars out.
The spoiler - Very difficult to find an NOS piece. And as you have experienced, they do not age gracefully, making good used ones almost impossible to find. There a couple of fiberglass ones out there, from Hawks Motorsports and Classc Industries (I think). From what I have read, the Hawks spoiler seems to get better reviews for styling (more like the original, though not a perfect copy) and for fit (though with any piece of hand made fiberglass, you can expect to spend some time making it fit). Also it is not designed to use the forward mounting points (but can be modified to accept them).