Greg , the above would be enough for the caddy , some 6x9's connested to a good quality head unit ,most have a 4 x 50 watt amp built into them , in my verts case cause i had no parcel shelf i opted for a boxed 12 inch sub in the boot and some 5 1/4 inch split's(midrange,tweeter) in the rear just below armrest, a subwoofer can compliment any type of music not just doof doof , i run the splits of the cd player and the subwoofer has a amp connected to it , i fitted this set up myself , if you need a hand let me know.
cheers chris.