stereo in 69

my friend has a 69 bonneville this car is in cherry condition all factory. I dont want to take out the factory headunit nor do i want to cut drill or rip anything in the car. The idea is to give him a premium sound system without damage to the car. If anyone has gone threw this let me know what you did i have done stuff like this before but never this stressful (everytime i get an idea i find a reason it wont work)

if you have any ideas let me know at [email protected]
or on aim at compye386