Help choosing ECU for S4 NA
 

It will be a track car for fun, nothing special, minimal tuning. The only requirements are installation in stock harness and possibility to read via PC all stock sensors data. Any recommendations?

Power FC with a Banzai adapter harness is your best bet. Yes it is older, but it has no bugs and does everything you need.

^The highlighted statement above really limits your options to an Rtek 2.x, but that one doesn't talk directly to a PC/laptop -- You'll need an old Palm pilot as a user interface for tuning/logging. Besides, unless you install a new factory harness, using the original S4 harness, which is now over 30 years old, probably crunchy, corroded & electrically questionable, is just asking for trouble.