[Cube] Upgrading my cube

[alaain at wanadoo.fr]

Hello all !

I have an old original Cube 450 with 637 Mo ram. I bought it new
five years ago and never had any problem with it.

But today I like to upgrade it to something more perfomant.

What do you think to be the best compromise in term of
CPU, HD and stockage capacity (CD or DVD ?).

My Apple dealer told me there was no really solution with
good fiability and good price??  But he told me also I better buy a new 
Mac mini.
So I don't trust him.

Is there somebody to  tell me where to find somebody in France
to provide and change the parts.


Thank you for your help.

Alain