I think dynaudio used to make speakers for the car and they probably still do. I used JL Audio 12" woofs in my 4Runner with 40/ch Fostgate amp and Alpine head unit. Left the stock tweeters and all other speakers in place.....it was a lease. Even with all stock speakers in place plus the stuff I installed, the system kicked butt.
JL Audio makes very good woofers.
JL Audio makes very good woofers.