you can but if you have a stock amp then your in trouble at least it will be more of a pain, you have to reroute the wires back to the headunit. as for adding 10 speakers to a stock deck you would want a amp to take care of that not the headunit, I just got a disco also and have been huge into stereo's for a very long time (installing) but I haven't gotten motivated enough to mess with this one, I kinda wanted to add subs in the rear, but I believe these cars have factory amps that run the speakers so it isn't a simple swap headunit thing, you litterally have to bypass all the wires and take out the stock amp. I did that same job in my BMW I had a few years ago and it wasn't fun, trust me, any good stereo store can do it but instead of the $30 headunit install it would be closer to $100 for the headunit itself. then the amp to run the 10 speakers. If you electircally inclined then do it yourself that is what I always did and you learn tons