as many here know, i am all for vmps subs - i firmly believe that it would be hard to match their performance w/powered subs, even after the cost of active x-over, amps, & wire are factored in.
that said, i needed a cheap sub fix for a second system based around the proac tablette 8 reference signatures. constant searching of ebay & classifieds allowed me to nab two yamaha yst-sw305's for ~$350 shipped. these now-discontinued subs have a pair of servo-driven forward-firing 7" woofers powered by a 200w amp.
using one was ok, but i was sure glad when i finally found the second one, about a month later. good subwoofin' requires stereo subs!

do these compete w/a pair of vmps larger subs? no, but they are quite respectable, providing clean, tuneful bass, & are able to energize the ~15x22x8 room i have them in... and, at ~23.5" tall, w/a narrow front, they'd make a decent stand for the 626r's.
yamaha has replaced these with yst-sw315's, which usually go on ebay (new) for ~$190-$200, plus shipping. but, these are a different design, w/one 10" downfiring driver. i don't know anything about their performance. and, also - i know audiojerry likes his yst-sw205's which are like mine, but w/only one 7" driver, and a smaller amp. his recommendation, among others, was what made me search out the yst-sw305's...
doug s.