new 330ci

hey guys, i just bought a 2003 330ci with everything in it on 18" alloys, and i am amazed so far :smokin: . the car's an auto, but it has tiptronic shifting. how significant is the power and acceleration difference when i switch to maual mode? and is this going to hurt the engine in the long run? also, what can i expect out of the car in general? thnx