your opinion please

i was wondering if anyone know about dynamat? i have found some http://www.uscaraudio.com/cgi-bin/usstore.cgi?user_action=detail&catalogno=10455 at www.uscaraudio.com (http://www.uscaraudio.com)want to know if i should buy it from them? does dynamat really help your speakers sound better?

thank you

andy