The problem of course is the 84dB/w low efficiency of the 3/5 (now called the S3), Spendor makes a DOUBLE-woofer version of it marketed as a center channel speaker called the SC3. It goes lower, and plays LOTS louder due to its much higher 88-89dB/w efficiency. Just buy a pair and turn 'em sideways to make a taller 3/5. OR get the similar vented 6.5" 2-way called the S3/1p, also at 89dB/w. You can easily resell the 3/5 for $600-ish. There's only so much you can push out of one 5" midwoofer, and throwing more than 100 watts at it gets to its compression limit, so you'll probably NOT be satisfied until you get more driver radiating area. Try a pair of the SC3 for best spectral match to the 3/5. You'll then NOT have to change your amp. Cheers.