ECU Comparison: Understanding the Basics

Hello everyone,
I have a question regarding the engine control unit (ECU). In my TDI, I have a 028 906 021 GC (Audi Cabrio) ECU, which is also used in the A6 models between 1995 and 1997. Based on this, I assume that not only are the pin configurations compatible, but that the ECUs should also be interchangeable.

Are all devices with the model number 028 906 021 identical in terms of their electrical components, and do they only differ in their software, which is indicated by the letters (e.g., 'GC')?

Basically, I need to obtain a control unit that is electrically compatible and has the same pin configuration. I don't want to work with the control unit's software; I need a good base for making software modifications.
Okay, here's a brief explanation: 028 906 021... I want to purchase software, have it modified, and then use it in my car with the modified injectors. After a lot of research, I'm finally ready to start the tuning process.

Is that possible?

1. Your tuner should be able to tell you which control units (ECUs) are suitable.
2. There is a distinction between models with and without WFS (Wireless File System) and between VW and Audi models. Therefore, not all control units (STG) with a specific number will be compatible.
3. Do a Google search for "Bosch Ecat" and see which other control units (ECUs) might be compatible.

Regards,
Sure, here's the translation:

"Guste" is a German word that means "gust" or "gust of wind." It can also be used to describe a sudden burst of something, such as laughter or anger.

Hello,
After reviewing the Bosch website, I found the following Bosch part number.
0 281 001 667
0 281 001 668
0 281 001 289
0 281 001 440
I find it under the cross-references.
Besides the Audi Cabriolet (8G7), the Passat 35i (until 10.94), and the A6 and A6 Avant models (from 07.94 to 10.97).
All models have a 1896cc TDI engine with 66kW.
The model Stg 0 281 001 668 appears to be the last in the series and may be able to replace all the others.
Unfortunately, I can't see which specific Audi/VW AKTE part number is being referred to.

Regards,
Schorsch.