I always wanted some seat time in a first generation supercharged Mr. 2.
I had a brief affair with and 85 GSL-SE and a second generation MR. 2 - both great cars.
If I had to chose I'd opt for the RX-7, there's a timelessness in that inital design that I think trumps the Mr-2's. However,
as for collectability, I've got to go with my sentimental favorite:
Another way to look at it, how many ultra clean RX-7's do you come across, especially right under your nose. If your Mr-2 is not as in good condition, you could always get an ultra clean Mr-2 down the road when finances improve!