1995 240 Aftermarket Install Options

[newmania240]

I ordered a new Alpine head unit (CDM-9803)to replace the factory system in my 240. I have already replaced the door (Polk)and rear deck speakers (Pioneer) and have installed a kenwood amped bass tube in the trunk. Crutchfield's doesn't have the install sheets for my specific car, but I know that it has that Clarion amp in the back and apparently there are some options.1)Should I rewire the entire stereo and bypass that amp now, or do I maintain my connections to the amp?2)I've also been told of a sleeve I need to order from a dealership to cover the hole I will have when I remove the tapedeck and the old CD player - anyone know a part number?3)Should I worry about replacing the tweeters which are still factory?4) Could I possibly ask anymore questions?

Anyother tidbits of advice someone wants to throw out is much appreciated. Thanks to whoever reads and responds to this...