Top bit of kit mate, got one in my vec c. Fit it yourself and save $$$. Great voice dialing, voice answering and diverting.
Oh yes, dont know if the astras use canbus but you will need to take a live feed from the lighter or something like that, unless it doesnt use canbus that is. The parrot seams to have more options with Sony Ericsson phones but will work with most bluetooth phones.