I'm currently sporting a gaping hole and probably a cracked paper cone in the dash of my 240.
The best and least invasive way that I have found to put tunes in an older car is to use a preamplified equalizer in a location of choice with an audio input wire run for an MP3 player to run radio and music.
Aside from being able to use the original AM radio, connected in conjunction with this system, it's just about financially worthless. Of course, with the exception of the MP3 player that unplugs and goes with you when you leave the car, you don't have to worry about someone destroying your car to steal pawn shop fodder.
i had the same set up befor with the amped eq but i hooked it up to the stock radio with a high to low line filter and yes the tape adapter
before... and i know what you mean about ppl braking in your car and tearing shit up. my car got broken in like 3 times and the tore up my gluve box cuz that wher i had my 1st set up - preamp eq 2-alpine cd player and 3- clerion eq (after i replaced the stock unit with a kenwood) but i fixed the glove box though
and thats just audio stuff one more time for my box full of tools. fucken dippshits tore up the hole rear left door to unlock the cake when they could of just broken the window... (i live in a bad part of los angeles) but i know have an alarm
and it loud and anoying cuz it just holds the horn on till it turns off ...