Converting Single to double din

Hi guys n' gals, I know I could spend hours wading through the post but thought this way would be quicker!

I'm bidding for a double din stereo on e-blag and presently have a single concert unit, my question is what is required to swap the units?

I'm aware I'll have to modify the heater controls(anyone done this) and probably going to need a new DD mounting.

Any help from your experience would be appreciated!
Chris............

should find all the info you need here

http://www.audiforum.us/