You'll be more than pleased that you made the change. I went from a 57 220d SE-L to an 06 250 SE-L and paid a lot more than you did to effect the change but, it was certainly well worth it.
It's a pre-approved jobby, one previous owner with FSH and I keep it under extended warranty and will probably do so until I decide to change it.
I loved the 220d, it was the best car I had ever owned up to that point but, as I do very little mileage now, I was somewhat concerned about any problems that I might run into with the diesel by doing such low mileage. The best car I have ever owned is the 250 that I now have. It is a dream to drive in every respect, long or short journey's, I just love getting in it. The acceleration is superb and I get good mpg returns too. Whether or not it makes a difference I don't know but, I never use supermarket petrol and I always add a touch of AR6200 at every fill-up.
Enjoy your car.........................I'm sure you will