I think you have done the right thing
. You will love the 330d. I dont know anyone who has driven one and not liked it. Buckets of torque and great fun to drive. I personally prefer it to the 335d as the single turbo gives a powerful shove as opposed to the linear smooth steady power of the 335d. This assuming of course the F30/F31 330d will be similar in power delivery to the E9X 330d.
To be honest, I dont think I would be that impressed with a 320d after owning and driving a couple of 330d's for a few years (no disrespect to 320d owners
). Each to there own.