I have only basic non DSP sound. In europe 3 types of sound system exist. Basic 6 speaker without amp, HIFI system - 10 speaker with amp and TOP HIFI 10 spk.+subwoofer with amp...
Basic 6 speaker system is really horrible /it doesnt have amp and crossovers../, it consist of 2 midbasses /piece of shit made in hungary with plastic chassis/ in front doors, 2 midbasses in rear doors and 2 midranges in dash. There are no tweeters!! So i removed midbasses in doors and installed new tweeters in front. Now I think those midranges in dash are not necessary anymore..
I have installed these components in front doors
http://www.canton.de/de-produktdetail-car-qs2.160.htm
tweeters install was w/o any problems..