Luv2listen,
I was in the same boat about a month ago. I bought M60s, VP150 and 2 QS4s. I felt like a good get a better sub for the EP175 money. I wanted a 12" speaker and didn't want to spend EP350 money. After much research I narrowed it down to an SVS 25-31 or PB12ISD.
I went with the 25-31 since the cylinder fit my room better. I had them tune to 22hz before they shipped. Overall I'm very happy with the performance all of the Axiom equipment and SVS sub.
You'd be hard pressed to find a bad review/opinion of any SVS sub.
