Head-unit, wiring etc advice

Hi,

I want better audio in my P12, simple. :)

How easy is it to replace the radio/player etc in the P12 with a store-bought one? There are plenty out there with a line-in that I can feed from the player of my choice (and my external satnav) - but the dash fitting for the P12 has only got the relatively thin fitting for the cd to be slotted in.

Is it actually fine? What should I know about buying a new stereo for the P12?

BTW it does not have a changer, it's just a single CD input. It's controlled via the LCD screen.

Alternatively, what other options to get a line-in?

I've tried those FM things and they're just awful, i'm no audiophile but I do expect it to sound at least barely tolerable.

Appreciate any advice.

Matt.