It was a BMW 135i (twin turbo) mate. 250rwkw on a basic tune with bolt ons. 😎The 125i is the NA version.
To the OP - I had one for 3.5 years and it was a fantastic car. The 2008-mid-2010 is the N54 twin turbo engine (same as in the 1M). The late 2010 onwards use the N55 twin scroll single turbo engine. They are both excellent engines and respond very well to tuning. The N55 is arguably more reliable but the N54 has better performance potential. The engines themselves are very strong. It’s the ancilliaries that are the common failure points e.g rattling wastegates, high pressure fuel pump, injectors, water pump etc. My car was perfect the whole time apart from a dead water pump at the 60kkm mark. Treat it with respect and it will look after you.
If you’re after a two door auto or dual clutch then I’d recommend a 135i or even a 335i (put some money aside for maintenance though). If you’re after a four door then like others have said, I’d go test drive a VW Golf GTI or R.
Happy hunting. 😊