mine is a 97 328i . i think its the 10 speaker system. i'll prolly just stick with a 4" 1way if thats the size, and replace them. but im not sure what the box is underneath. i tried it once before to pull one of them out by loosening the top 2 screws but i just couldnt get the thing out. so i gave up before i broke something.
sorry if i hijacked the thread