It is possible..
Either start from scratch with the wiring or splice into the original wiring behind the head unit
Upgraded HU this week. Now looking into getting Hertz or Focal components.
Managed to remove tweeters from the dash without taking the dash top off. Does the standard renault speaker system have any crossovers though ?
I have got a set of Hertz 6.5" Components going a a good price. Still boxed