new speakers and amp for Odyssey

I have a 2002 Odyssey.


I have the Alpine 7894 head unit (27watts RMS/60 peak x 4 channels)


I was looking at Infinity Kappa 63.7I ($95/pair) front and rear.


I would need an amp--The AudioBahn A6004V 4 channel ($145) was recommended to me.


Someone also suggested a Bazooka BTA8200 sub ($175) to go under a middle seat--I have my doubts about the quality of this one. I listen to jazz and rock, but I'm not into boom boom.


I am sure this would sound significantly better than what I currently have


The questions:


1. How good (considering the price) are the components?

2. Does the sub really matter in this set-up? The main speakers go down to 45 hz.


Any other advice would be appreciated--other options, etc.