I've upgraded our whole system with a Sony GT30RN Mp3/WMA headunit - see here for details of how to get one for only £47 The Mégane II Owners' Club :: View topic - sony at argos
- the headunit will work with the fingertip controls and dash display if you have the latest Update list CD unit fitted as standard. It also comes with a remote if it doesn't.
I've also fitted a set of 4 Infinity 13cm door speakers and a 760W amp powering a single 12" boxed JBL subwoofer.
My amp is away for repair at the moment and I'm undecided as to wheter or not to refit it when I get it back as the new headunit seems powerful enough on it's own.
Running the power supply for the amp from the battery to the boot isn't a job for the faint hearted - it took me about 3-4hrs
A new headunit and a set of door speakers should be enough of an improvement over the standard Renault equipment.
Hope this info helps