Yeah, i'm sure there are a lot of possibilities to make the system sound even better but, you know, it's often a matter of keeping the car in its original look rather than fitting aftermarket things no matter how good they are.
But probably in the case of sound systems maybe this matter is less important.
Never heard of Cerwin Vega but it seems they do nice products.
Anyways, i'll check the scheme of the sound system and see what pieces are needed and find equivalent speakers
Should be as easy as unplug the originals and plug the new ones, shouldn't it?