Sorry, WLDock4...I completely missed that one. I have no excuse. I'm definitely guilty on this one. I'd been concentrating my searches on exactly what you'd proposed.
I used the Aura 3" full-range with a Vifa tweeter in my last car. I still have them, actually (x3). What I didn't love was that the Vifas were a 6 Ohm load and the Auras 4 Ohm, which created an overlap in the crossover points in my Diamond Audio crossover (designed for 2.5k). I had some harshness which was either due to this or the windshield loading...you may have seen my windshield foam post... Those Auras won't fit in the new dash anyway because of their underhung structure.
I had my eyes on the L3 and some of the other ones reviewed in the post from last week covering a bunch of 3-3.5" full-range.
My main dilema is that I don't have a bunch of time to do this stuff anymore. We have a 6 month old and putting a few hours together at any point is just about impossible for me. So, if someone said "those Infinity Kappa 3.5" are as good as any 3.5" DIY" I'd just do that...
I'm running them as the top 2 run passive in a 3-way, so I don't much care about bass response unless they're so good that it would make sense to lower their high-pass and the low-pass of the Morels.
I've run the SoundStreams in 2 different configurations:
1) With the Diamon Audio crossover. The drivers are 3 Ohm, so this should be creating a dip in the FR with the low-pass somewhere below 2.5k and the high-pass somewhere above 2.5K. The "crossover" that came with them was a 12dB high-pass @ 9k (natural roll-off for the woofer). When I started hearing the buzzing, I thought it was coming from the tweeter...so I switched back to...
2) Original 12dB high-pass on tweeters @9k and natural roll-off of the woofers
Both configurations are being sent a high-pass signal at about 350Hz via the on-board crossover in my amp. The amp is rated at 100 Watts regadless of impedance (i.e. 2 or 4 Ohm). The speakers are rated 75W RMS, 150W Peak...but the gains are very low to balance them with the rest of the system.
I was surprised to find that it was the woofers doing the buzzing. They were only being sent between 350Hz -<2.5kHz...and not being blasted. It was the tweeters I was worried about, getting more than an octave reduction in their high-pass.
Thank you very much for giving me that post...again, I'm sorry for not doing the search this time. It obviously would have come up right away. I'm dope.