tweaks that impress the unsuspecting


What I'm interested in are tweaks that impressed friends or significant others WITHOUT being told beforehand that the tweak was done...If they were tipped off first, it doesn't count.
desoto
One of the best tweeks bar none was the addition of an Auralex "SubDude" isolation platform for my sub. Best $50 ever spent on audio. Unbelieveable, kills any unwanted vibrations and resonances that muddy the sound.
I second Oddiofyl's observation re SubDude. With my Velodyne HGS-15 and HGS-10 the SubDudes removed the boom and extended the bass.

db
Question: Anyone ever compare SubDude sub isolator with  IsoAcoustics Iso-200Sub Subwoofer Isolation Stand? They both are about the same price and with my wooden floor I need help with my SVS PC-2000! OR maybe just some cork blocks under a solid paving stone?