I would hold off for the JBL mate. Or get the Infinity Basslink-X with the 10" live sub and the passive radiator, as its excellent value and would come in cheaper than the sony subs and amp by the time youve bought boxes for the subs, etc. To be honest its worth the difference to go to a better brand. Either that or go for Pioneer or Kenwood for the same money as the Sony stuff, as it really isnt that good.
Not sure about their new pentagon-shaped subs and amps tho, to be honest havent had any experience of that yet, but knowing what their previous stuffs been the quirky shaped gears likely to be basically just a gimmick, and the pentagon-shaped design gives absolutely no acoustic advantage over round subs!! (just like the old 6x9s/square solobarics vs round speakers debates!)
All of the above is just my own view, and Im certain evilice, john and many others will all have their own opinions to contribute as well!!