I'm considering a new subwoofer - and 2 in my hot list are a 2nd hand Q100e OR a BK XLS200 - now without being able to listen to either to compare I'm struggling. Would these 2 subs be fairly comparable ? The REL Q100e seems a bit bigger and bigger than the preset REL Q200e etc - and has a 12 inch front firing unit - but then only has a 100W Amplifier. The XLS200 is smaller, smaller drive unit and has a more powerful amplfiier ? The price for both is very similar - any advice will be appreciated Thanks, Mark.