It has the ability to run an AUX in via a seperate module, but other than that is only a basic head unit with basic functions. Very high level on CAN coimmunication with teh vehicle including Audio outputs - No, you cannot simply wire speakers into the rear of the CD30, even the outputs are non standard.
DVD90 was certainly launched to the UK market, but as an option that cost the price of a second hand Corsa, was not taken up by many, so fairly scarce to find.
As a "general" guide (excluding the NCDXXX and CCRTXXX ranges and of course BOSE) the number of digits in a vauxhall stereo name also indicate plug and play interchangeability. ie, a 3 digit model can generally be interchanged with another 3 digit stereo. A CD300 / CAR300 / CAR400 / CDR500 / CCR600 are all interchangeable with each other, but not with 4 digit models. And the same can be said for most 4 digit models. CCR2006, CDR2015, CCR2005 etc. And the same for 2 digit models which incidentally are not compatable with anything before 2005 either.