I am thinking of buying a Paradigm PS1000 or a PDR10 subwoofer. Firstly, does anyone know shops that sell them, apart from Richer Sounds ??? Also, if anyone has one for sale second-hand let me know (I am based in London). Is there a lot of difference between PS1000 and PDR10 ? (I heard PDR10 is lacking some kind of crossover feature, but since I am not a professor in home cinema, i woudlnt know what it means even.) Alternatively, i may consider an Eltax A10. Then again, is it comparable to the Paradigm subwoofers in terms of performance for money?