I am not that familiar with the e46 HK system, but on the e36, there are small twetes in the same pod as the rear speaker. Its possible theere are two in there you missed when counting. Dont have any ideas or info on the others though.
<span style='color:gray'><span style='font-family:Courier'>1995 e36 3 Series RIP
1999 e46 3 Series BURN IN HELL
2000 MR-S Roadster= Current</span></span>