Having added an Opus 21 to my system recently I've been through the usual experimentation with cords and tweaks. Trying a suggestion from another Audiogon thread brought a surprising improvement that includes better bass definition; you may find it equates to "slam". Check out the thread in "Tech Talk" under "Copper Sleeve over IEC"...
http://forum.audiogon.com/cgi-bin/fr.pl?htech&1237170946&openfrom&14&4
Hard to beat a $5 tweak that works!
http://forum.audiogon.com/cgi-bin/fr.pl?htech&1237170946&openfrom&14&4
Hard to beat a $5 tweak that works!