Anyone find a drop in replacement for factory squawker?

I have been researching this topic (ad nauseum) planning for the upgrade in my Package IV with JBL/Nav. I've taken the dash squawker out a couple times to measure the opening. The factory speaker is 2.5 inches. You could certainly do an aftermarket 2.5" or 3" easily enough. You could probably even squeeze in a 3.5". You cannot get a 4" to go (I had one & tried...won't work). I really wanted to try getting a component set with 3" mid & 1" tweet in there, but that would require fabricating a new grille/cover, which I didn't want to do.
At this point, my first choice for a direct replacement is the Tang Band W3-1364SA (Tang Band W3-1364SA 3" Bamboo Cone Driver | Parts-Express.com) although I havent pulled the trigger on it yet. Upgrading the JBL system is a serious pain to do well if you want to keep the factory head unit...I'm looking at getting a JBL MS-8 to make an aftermarket amplifier possible.

 

Keep in mind - the grill opening (for sound) is as I remember 2.25".

If you are not playing with that, I'd highly recommend the MB Quart 216s. The tweeter is more like 1.5 - 1.75", and puts more range up front. For a simple install, you could just dab a bit of hot melt on the grill sides(round sound opening part). I think this would be pretty easy.

I'd guess you are going to get better sound form a matched set of components...

 

I would also look at the resistance b/w JBL speaker and aftermarket unit, esp. if you're gonna keep the stock JBL amp. Isn't the JBL squakers around 2 ohms?

MB Quart tweeters can only go down to 2900 hz in their premium lineup. My guess is that imaging and staging will be messed up if one were to install MB Quart tweeter in squaker location and 6.5" woofer in the stock door location...both of which are directional speakers and, with the stock locations, these speakers will be firing in different directions! In addition, the MB Q tweeters have wide dispersion...how will this affect its under the windshield location? MB Q designed the tweeters to be placed on the door A-pillar or close to there, where wide dispersion is a good thing. Under the windshield, it may not do as good. And knowing how bright the MB Q tweeters are (i had Q series many years ago), the stock locations may lead to harsh bright sound!

Just my thoughts.

 

It would be very nice indeed if there was a simple out of the box component set that would work....but most of those don't have tweeters that play down low enough to reproduce the frequencies that the factory system does....and I agree that this would likely impact the sound in a way I'd like to avoid.
There won't be any impedance concerns if I use the JBL MS-8 and an aftermarket amplifier to drive my aftermarket speakers. I'd simply take the high level outputs from the factory amplifier and use it as inputs for the MS-8...then go to the aftermarket amp with line level inputs that have been flattened, summed, and then crossed-over, eq'ed, and time-aligned. My goal is to get the best possible sounding drivers that will go into the factory locations in a stealthy, factory-looking way.