Originally Posted by kardboard
The Alpina is something more than just a 335d though. The motor is a reworked N55 (made to have 2 turbos), and this one like OP said can be ordered with a LSD. Add all he Alpina stuff like trim, seats, dash, wheels, quad exhaust and this is much more than a 335d.
They must have seriously reworked it to get a petrol engine to run on diesel
I think you'll find they most likely use the N57 which in the 335d already has 2 turbo's.
I know the Alpina has other changes to make it unique, I was merely mentioning that it's not much faster / more powerful than the F30 335d. It'll be a hell of a lot more expensive and more so once you see what the finance deals are if you go that route. BMW in the UK are doing 3.9% APR and around £7 - 8k discount on a 335d but an Alpina will be more like 7 - 12% APR with no discount.