Hi guys,
I have a couple of questions about the opel omega I drive for the past year. It's 2002 with the BMW I6 Y25DT and the 5L40-E 5 speed auto gearbox. I know that engine and transmission are N/A for the vauxhalls, but I'm sure you'll give me some clues anyway

So, I read that the software of the transmission can be updated, but I can't find much info on the topic. Can I do it myself? I am from Bulgaria, and no one here, including the Opel dealer, wants to do this for me. I'm not a beginner and I have the OBD2 interface. I just don't know what I need to do.
I also know there is a way to "revive" the missing horses from the bmw engine. I mean the same engine on a BMW is 163HP, and not 150. this is some marketing shit opel did to have different specs from the bmw. As far as I know it's done by repositioning the timing belt. but the problem is that the 5L40-e gearbox is rated for 340Nm. Now the engine gives 300Nm and after such procedure it will be more than 340Nm. BMW also put this tranny on 330d so I don't get it! they even have it in the x series. how come it handles more than it's made for? how can I reset the timing belt (a local former BMW dealer does it) or chip it without having to buy a new transmission after 2k km

?
I had more things to ask, but can't remember now so..

Thanks