Replace stock speakers in VZ

[DavesSV6Tonner]

Speak to a reputable local Car Audio shop. They should know what you will need.
Last year I had a pair of Kicker 6" Coaxial 100rms KS Series (45mm deep) fitted to my VZ.
A big improvement over the OEM Korean rubbish Holden's fitted.

 

[Jezza]

If your going to be fitting better speakers to your VT-VZ I'd highly recommend putting in an MDF spacer in. Aerpro do a 16mm MDF spacer and it'll help absorb the vibrations from the speaker giving a much nicer sound. I've put some Alpine Type R speakers in my WH and even though my amp isnt powerful enough to give them full power when your cranking the system you'd not care because its crystal clear and no vibrations from the doors

 

[Sandman.ute]

If your going to be fitting better speakers to your VT-VZ I'd highly recommend putting in an MDF spacer in. Aerpro do a 16mm MDF spacer and it'll help absorb the vibrations from the speaker giving a much nicer sound. I've put some Alpine Type R speakers in my WH and even though my amp isnt powerful enough to give them full power when your cranking the system you'd not care because its crystal clear and no vibrations from the doors

I bought Sony 6.5 Inch Component Speaker Set XS-FB1621C in the doors/dash and was going to add Sony XS-GTF6939 3-Way 6x9 Inch Speakers behind the seats, then hook them up to Sony DSX-A410BT Single DIN Head Unit with Sony Amplifier - 4 Channel, XMN1004 ... installed professionally