How clever is opcom.i did reply to a post not long ago but lost it so is it just a diagnostic tool.can the a/c be switched off with this and the egr can you turn it off so it stops working. What other functions does it have.
I could be wrong but i think you need to use tech 2 to remove egr function from the ecu, Plus i think it can only be done on vectra C and not the vectra B. Not sure about the astra and zafira models. Someone else might to help you with that

I think it is useful for most other functions like management light, fault code reading, Airbag light , Easytronic programming etc.
Been a while since i used it, but for a clone device and the price i would say it's pretty decent .

Not sure if there is a newer version out, would need to check that out.