New Stevens Audio Midbass MB-8 2 ohm - Car Audio | DiyMobileAudio.com | Car Stereo Forum
A very high sensitivity of 101 dB @ 2.83 volts or 95dB @ 1watt (1.4 volts) allow this driver to excel with very low distortion even at higher listening levels.
With an Fo of 56 Hz and 1-way xmax of 5.5mm...
You could aim the tweeters on-axis to you ears. Screw the passengers, they are too drunk to appreciate good music anyway. Delay the left tweeter, 1-2ms. Take a laser pointer and align them with the side of the headrest.
Double sided tape and/or a towel to demo the tweeters a day at a time. There is no right way. Sometimes on axis. Sometimes aimed across to the other A-piller. Sometimes aim at the mirror. It is car dependent. You must experiment and see what sounds the best for you. I have even heard of...
Here is a third option.
https://www.amazon.com/Soundstream-T5-2500DL-Tarantula-5-Channel-Amplifier/dp/B00VKWIE00/
I run this.
The crossovers are very nice and the Sub channel is 750w x 1 @ 1 ohm.
I removed my Kenwood Excelon from the c5. I might just get a newer one. eXcelon | CAR ENTERTAINMENT | KENWOOD USA
Upgrade with DSP later on.
Thinking this...
http://www.kenwood.com/usa/car/excelon/ddx794/
or
http://www.kenwood.com/usa/car/navigation_multimedia/ddx774bh/