'86 afr tuning
 

I have an '86 (s4 NA, heh heh duh)

i was interested in the stage 2 RTEK tuner so i could achieve results like this guy did
https://www.rx7club.com/rtek-forum-168/thumbs-up-s5-na-2-0-a-668832/

but, the RTEK is only offered for the '87 and '88 ECUs.

i would like something has similar functions as the RTEK

what is out there?

The 86 ECU is the same as the 87 ECU. I've got an 86 and the Rtek 2.0 it works fine :)