YES IT IS POSSIBLE,
i have just fitted one of these to a mates standard vauxhall corsa
Audison SRx5
coupled with some genesis a16.01 components and a sub of unknown origin (there is nothing on the sub to indicate what it is)
i have to say i am VERY surprised as to the quality of the sound
he wouldnt tell me where it came from or what price he paid, but you should be able to get hold of them from any focal dealer
instead of using RCA cables to carry the signal from the HU, it uses the existing speaker cable, seems to work seamlessly