Device turn D-jet into close loop system

I was learning on d-jet.
Yesterday, I read on a forum, someone mention there is a device which was from EU region i think, that can monitor the CO level and react to the D-jet ECU by modifying  the Resistance value of Engine temperature sensor.
I want to know if this is true, or is thus kind of thing actually exist. It sounds pretty do-able, and can truely turn D-jet into close loop.

I found a little bit of information. The company sell them is Gutman or GAT. But i still found nothing about them

Yes,
there were companies in the Ninetees that adapted a catalythic katalysator to the D-Jet-system.
They did it because one had to pay very high fees for cars without such a system - nowadays classic cars in good condition can get a special document that minders the fee.

Because the systems were known as another factor for producing trouble, most systems were removed from the cars till nowadays.

There is some information here in the forum - I'll try to find it for you.

Regards
Norbert

edit: Have a look here <maybe using a translator>: jetronic.org/en/forum/jetronic/150-m110-...-tuning?start=0#1057
some more here: jetronic.org/en/forum/jetronic/178-st28-...unktioniert-das#1373

So in general, such a device is nothing but bring more trouble into D-jet world?
I was hoping such device will help on bring the D-jet to a kinda close loop injection device. But it looks like it is not.
Also, anyone have experience on Megasquirt? At my understanding, only thing needs to be change is the TPS, and all other can stay? With an additional O2 sensor, This sound very promitive, but what benefit can it bring compare to D-jet?