I recommend HARDWARE + SOFTWARE :

MPPS

OBD ->> programming <<-  if extra wire from pin43 (ecu) runs till obd-port.  You only need to add 1 extra jumperwire on the obd-port
(12v) and all is sortend for ->> programming <<-   NOT READING.   

I clearly state it like this, to prevent false assumptions of been able to read. As thats NOT the case, and untill now NO tool has been
able to read the flashrom. E2p-rom is readable with KKL/vagcom-lead and monoscan.

3 minutes flat, programmingtime with mpps for the 256k flashrom.

Benchharness : Thats a D.I.Y.  one, containing 5 wires..   I made it myselfe. SOOO easy.... to create and use !

Cheers,

PvL

so that means that I can disable the rear o2 sensor? -> Ofcourse ! You have a lot of motronic programming experience, so you will succeed !!!!!

Now, the big question... my ecu is chipped by APR  -> thats a statement. Not a question

actually when I put it in CEL shows up....  -> Great, throw it out, and be happy with a custom-tune that don't need apr hardware. Way more flexible
to work on. APR has used a copyprotection-solution, and that will be giving you issues when wanting to update the tune.