But in general, I believe 07 cars made before Sept (09/07) use the 300 while those afterwards use 312. It depends more on when the car was made rather than for which market.
Pretty sure the OEM ones are NOT ceramic.
A lot of guys typically get Hawk HPS / Akebonos mainly to reduce brake dust as most do agree that the OEM are actually pretty decent pads, they just generate a lot of dust. Really depends how you intend to use your car (ie. track, strictly street driving, etc).