I apologize for bumping this old thread, but I would like to share my experience in this matter, since when I was looking for good advice on this topic for myself
It has been my experience that comparing sensitivity ratings from brand to brand is unreliable. Side by side comparisons on the same power often reflect a different outcome. Not all brands provide honest specs. Not all specs use the same qualifications, such as weighting, etc. The sensitivity rating may reflect the 'peak' rather than the 'average' and I do not want a peaky or erratic sounding speaker. Generally the more linear speakers will have a slightly lower sensitivity, whether marine, car or in home. A 1 watt sensitivity spec was very useful in the day of tube amplifiers because the power was so limited. In contrast, today, big power is relatively cheap so the speaker designer/builder has more options in choosing his objectives.
It may seem like a small distinction but there is a difference between sensitivity and efficiency. A speaker with a very short voice coil winding could have a sensitivity advantage at 1 watt but can quickly lose its effectiveness, or efficiency, at higher power levels with longer excursions. A speaker with a lower 1 watt sensitivity rating could actually play louder with 50 watts and provide deeper bass response.
I am sadly well versed with the "Bose for hire" system label, the EQ was set to preform within a certain specification with some adjustment available to the user. If someone can rebut me on this please do, as it would be nice to know if they have corrected their ways and demand on installing their own componentry again. The 80's Cadillac Bose system is a great example of at least partial proprietary componentry, using star drivers for front fill, plus specific amps (forget what the rears were). The same setup was also found in 80's Corvettes with some EQ and amp changes for the difference in layout and noise level.
My current car has the Bose moniker attached to the speakers and it sounds terrible, like i'm listening with wax paper and tin cans over my ears. I dream of having the JVC/CDT setup that I threw in my last work car. But that was not factory. I guess I could have been more specific on component breakdown and their true place in the reproduction of sound, but this is an open ended discussion targeted towards everyone here, with the encouragement to add technical details if they have the info readily available. But I digress
There are many interesting videos on YouTube, I'll leave one of them here, I hope someone will help in the future.