Have a 92 mx3 gs. The seats are murder on my back I was wondering if 626 or mx6 seats fit.

 

I also attempted to replace the front seats in my Mazda MX-3. I found that the narrowness of the space and shape of the floor made it very difficult to find a seat that would fit. In the end, I retained the stock seats. My recommendation is to find a good automotive upholstery shop that will rebuild your seats with extra padding in the proper locations, e.g. lumbar support, under-thigh support.