I have a question about RX-7 CPU's. Mainly the one under the passenger side carpet. Is there any differance between years and models? Cause I bought an 88 GXL and was wondering if it would improve my 87 Sports performance. Thanks for your help.

 

That is the ECU, not the CPU. Yes, there are some differences between years. Swapping 86 vs 88 (or whatever) will not improve performance.