You can buy an alpine HU, or lower model Pioneer HU and keep the stalk controls. i think the only one that keeps the display as well is Sony. But check the FAQ and other posts - theres stacks of info on which type of adapter are available for different head units. Theyre pretty expensive though - well, theyre more expensive if you have to convert pounds to australian dollars, then pay for importing like I do
Anyhow, you say best/cheapest... i think theyre mutually exclusive if you put that / between them.
Best option would be to replace the whole head unit and get a decent 3rd part one. The display on the 3rd party one will be better than the car display anyhow, so who cares about keeping that. You can get an adpater for the stalk controlls for most good 3rd part units and the cd player sound better too. If the 3rd part stacker is too expensive, then think about an MP3 playing head unit. The alpine ones are pretty good. Then its the equivalent of a 12 disc stacker on each CD. Keep a CD wallet and youve got 120 discs right there.
I dont know if youll be able to get a CD stacker that is compatible with the factory CD player. Im not sure, but from what Ive been told by other people, theyre custom ones.
Dont bother getting a CD player from a later model, unless its the stacker that you want. Unless you can get one for really cheap, then get a 3rd part one.
Having said that, in a couple of weeks time, I might have a 2002 model Clio HU and stacker for sale...
Scott.