I almost did a trade like this with our well known member mykarisvicious. Difference is I have an auto pearl white hard top NA versus his stock s2k with amuse front end. I had no money, car was starting to need maintenance and it was my DD. Nothing wrong with it, I loved it but wanted more. That to me is a better trade, both cars being about the same as far as speeds go and both have potential. But being broke the Honda being lower mileage would be better for me as far as what was needed in costs to afford owning one for a DD. In your situation I'd of only traded if that were the case or if this guys car in your eyes is worth more. Not only in how it stands now performance wise to your car but also in value. I like those cars too, but if you had a TT I wouldn't unless it needed a lot of work to get it to where you liked it to be. Maybe a color you don't like and etc or if the s2k was just perfect with the mods it has now. It's your call, sometimes it's not always about brute power. There are other cars out there you may enjoy over the supra in actual driving.
I never did the trade in the end. I figured I'd go through the pain for awhile because I knew this hard top would be perfect to build upon. I'm starting that dream now.