If you are looking for the size of the alloy 5 spoke wheels like on most 94 GT's, their 15x7 just like the one pictured below.

And if you try to order them from a dealer, make sure you know which one you want because it comes up with 2 different part numbers.One is about $30 more and it does'nt match the color of my wheels.My wheels are a solid color, but the wheel that will show up if you order the higher priced one, will be the same color except for the area in between the spokes.It looks like a darker shade of that same color, and also looks clear coated.I bought one off ebay and it came in a toyota box with the part number attached to the side, but I have not seen a celica yet, to have the same wheels on it like this wheel.When I asked toyota about it, they said they showed 2 different part numbers but neither showed a picture or even a description, so I figure the other part number is probable the one like most cars have on them.
It might also be the same wheel I saw on a ST coupe the other day too, so make sure you ask them if it is'nt the right wheel you can replace it with the other one.

If you order the cheaper one, let us know what you get when it comes in.