Not to beat a dead horse into the ground...but I went through all the posts, parts lists and summarized the parts needed to do the 18 speaker Harman Kardon updgrade. If you order the kit #82213535 (approx $450) you will end up with an extra speaker (center dash) and an extra subwoofer (behind seat). In addition to that kit, you have to order 2 subwoofer encosures which is about $100 for the pair.
Here's the boiled down version of exactly (or what I think is exactly) what's needed to do the upgrade. You'll save about $200.00 going this route. I'm assuming the subwoofers have speakers within them and they are counting those as well +2. I added an extra nut and screw to the list...just in case. If someone notices that I missed something...let me know.
Part Number Part Name Price Quantity Total
68223032AA RT door Grille-Top Speaker cover $28.81 1 $28.81
68223033AA LT door Grille-Top Speaker cover $29.40 1 $29.40
5035290AC top door Speaker $26.92 2 $53.84
5035253AB 6x9 Speaker Sub $57.94 2 $115.88
6509822AA Speaker Nut for top $2.06 5 $10.30
6505628AA Tow Eye Cap Screw $3.39 5 $16.95
5035339AA Enclosure-Subwoofer $46.29 2 $92.58
Subtotal: $347.76
