For the fronts I used a 2 Ohm speaker to match the original speaker impedance, so I used this :
I think nothing is worse than stock speakers, neodymium magnets or not.
That is correct for the front (doors). For the rear shelf speakers, you will have the same volume (or just as loud if you want) as rears are also 4 ohms ( in practice, it also depends on the sensitivity of the speaker, but for the sake of the argument, we can ignore that, as usually aftermarket speakers are more not less sensible, so volume is slightly higher if anything).
My question pretty much is why an upgrade of those tweeters is not necessary? Seems you're saying the stock tweeters in the doors and a pillars are decent enough quality to handle the treble? I have the track pack so I'm also missing the dash speaker.
If you look at the speakers I used in the doors for replacement, they do have a tweeter on their own and a crossover built in. They sound great and complement more than enough the treble provided by the A pillars, so I didn't worry about the a pillar tweeter . But if you think you need one, it's easy to replace...
I really doubt speakers are different sizes or quality, but I don't have a Tech pack. You can easily do what you plan, upgrade door and parcel shelf speakers, and maybe install a small sub in the tire well, driven by the high level outputs of the rear speakers. But you would need a 2+1 channel output amp in that case, as you need to take inputs from rear speakers, and if amp is mono, nothing to drive them anymore. Which is fine I suppose, but you loose all feedback from the rear, in exchange for good bass.
Damn it, I though Harman Kardon is a leader in audio and a good brand name. You learn something every day.
