hey dcrusupra, nice choice of cars...
anyway, on to the topic...Spycialost9999 you can buy some spring spacers from your local auto parts store. There are 3 different types: type one is a set of rubber blocks that you can squeeze in between the coils of the springs once you take the load off them, they are non adjustable. There is a metal type that have a sort of screw in function that you get some adjustablility depending on how far you screw them in between the coils. Then there is a clamp type (normally used to lower the springs by clamping the coils together, but can be reversed so that that you spread the coils farther apart.
All 3 should give you enough lift and in effect raise your spring rates at the same time. I cant imagine doing this to a Supra, but if you need to do it, these "lift kits" should be the easiest and cheapest way to do it.
PS. spycialost9999 - please pay for your TEMS actuators on Ebay...lol...Im not waiting forever!