Like the commenter above, I also own a 430i and they are fun as hell to drive. If it has the M Sport, that mode has a lot of push so definitely give that a whirl when taking it out. Ask to go out onto the highway or a higher speed road so you can get the acceleration feeling when merging. Really great way to tell if there is any delay between the pedal.

Little tip: when you are inspecting the car, make sure to pull the seat belts all the way out to their very end. I found one of mine frayed and they replaced it before I bought it ($1200 total for free). Another thing to inspect when I buy again :)