I'm not saying you can't get better sound in a new car with after market gear. It's just that the gap in sound quality is smaller. Depends how fanatical you want to get and how much you want to spend.
My last car had a very good setup and sounded great. My head unit was a Pioneer P9 with the outboard digital eq/crossover box. Into a 4 channel Tube Driver Blue amp for the fronts. For tweeters I used the totl Morel soft dome. Midbass drivers were 8" Dynaudio. I used the Pioneer P9 for the crossover. The P9 also had a 31 band eq. I used a RTA to adjust. For subs I had 2 12" Eclipse driven by a Rockford Fosgate digital amp. Being able to adjust eq for the car environment is very helpfull.
In my new car I did not want to cut up my door panels to accomodate the 8" mids and big tweeters. So I just used some older Diamond Audio Hex series I had behind the existing grills. My Pioneer P9 finally died so I just got the new Pioneer PRS80 which is much less expensive but has most of the same features of the P9. Unfortunately it does not sound as good. I miss the other speakers so I may find a way to install them in this car.
My last car had a very good setup and sounded great. My head unit was a Pioneer P9 with the outboard digital eq/crossover box. Into a 4 channel Tube Driver Blue amp for the fronts. For tweeters I used the totl Morel soft dome. Midbass drivers were 8" Dynaudio. I used the Pioneer P9 for the crossover. The P9 also had a 31 band eq. I used a RTA to adjust. For subs I had 2 12" Eclipse driven by a Rockford Fosgate digital amp. Being able to adjust eq for the car environment is very helpfull.
In my new car I did not want to cut up my door panels to accomodate the 8" mids and big tweeters. So I just used some older Diamond Audio Hex series I had behind the existing grills. My Pioneer P9 finally died so I just got the new Pioneer PRS80 which is much less expensive but has most of the same features of the P9. Unfortunately it does not sound as good. I miss the other speakers so I may find a way to install them in this car.