Have seen the KEF subs on Ebay ( the 2500 and 3500), Has anyone any experience of these and are they good for the money, ( £200 and £300 respectively). I have KEF surround package made up of IQ5SE fronts, IQ2c and IQ1 rears. Am I better sticking with a KEF sub, or anyone other recommendation for around £ 300 - £400 ??????? Helpppppp