Car audio system

Thanks all. I have narrowed the search to an established company that sells Alpine and JL among others.

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.

Audphile1 - Yes, Dynaudio still make car speaker drivers, and they are among the best, alongside the likes of Morel and Seas

JL subwoofers are OK, but if you've been listening to a REL / Velodyne DD / other high-end sub... don't expect much other than "boom boom"