I remember back in the day...around the early 90's, when center channels
were REALLY, REALLY popular, I knew several people who used 4" MB Quart
coaxials (because these were the best coaxials you could buy at the time)
and would just mount them right on their dash wherever they could find room.
A couple of guys actually used squares of carpeting as a mounting platform.
As I recall, ALL of these approaches always looked REALLY ugly. I must tell
you, I was relieved when the center-channel craze ended and I no longer had
to worry about it. Well, it's back, and now there is actually a REALLY good
reason for it (Dolby Digital).

Let's face it, in most cars it is hard to build a good sounding AND
attractive center chanel.

MOSFET