Corsa B CD30 Replacement?

[Dexter619]

Hi
A bit new to all this sort of thing (apologies)
I have just bought a corsa b for my first car, and it came fitted with a CD30 radio system. I have been told that i can remove this unit (excluding screen etc.) and have it replaced with just a surrounding which i can place a new separate head unit in, is this correct?
And also, i was wondering if this is the case whether anyone could help me with knowledge on a good sound system, head-unit and speakers with preferably a budget of under £150?
Thanks

[Dexter619]

Correction - HU is CD30 MP3 - But been looking over various other forums today and found that changing the HU would be my best plan for better quality sound etc. as the front speakers at least are decent enough if the line is amped to all 4 speakers?, or this is what i've heard. I don't know the rms of the car speakers if anyone has the knowledge that would be muchly appreciated But new HU and have it amped is what i've heard are the first best plans for what i want to achieve.
And to use http://www.bluespot.co.uk/car-audio.aspx/caw1232-0... and purchase one of these to go inside http://caraudiosecurity.com/shop/product_list/c_pa...

Edited by Dexter619 on Wednesday 2nd June 18:13