tweak, do they realy bring improvement?

not all people have ac issues or problems and it is impossible to say everybody needs a line conditioner. you will not be able to turn the sound of a $100 sony amp into the sound of a $30,000 sounding amp by hooking up a line conditioner. a good line conditioner will allow good equipment to sound their best, not make them better than their best!
if we are talking about ac issues, IMO, balanced power devices are the trick. these are not line conditioners that filter the line, but rather a total different approach of how the power is presented to the equipment, using inverse phasing. I have seen demos of this equipment and it made a big difference in the sound. i am going to use balanced power in my next house for my audio and video rooms.
as for tweaks, maybe DAZZDAX doesn't need them. he doesn't specify his equipment, but he could have an audio stand that is made out of steel that weighs hundreds of pounds (like the rick racks stand at HE2003 in the pipedream room). maybe his speakers already have spikes. maybe his equipment has the isolation needed to reduce vibrations. I saw many turntable setups that came with some elaborate stands, in which i don't think a few $100 cones would improve the sound for these pieces.
maybe he is just happy with listening to the music and not judging his equipment! what a novel concept.

Some do, most don't. Listen before buying, if no money back
warranty is offered forget it. One last advise, the ones that do work stay on the market for quite some time, the other ones are "fly by night". Just try to look around for
cd stabilizer mats & cd's edge markers, maybee one or two manufactures do have them in their lines.

Repends on the capabilities and deficiencies of your system. I had one of the great ears in audio come to my home from New Jersey this weekend . My friend Dave said my system lacked one critical component. It just happens to be from a company that posted above. He said his friend Barry from Bright Star Audio makes incredible and affordable isolation devices that will breathe life into my system. Disclaimer : I am NOT a dealer but I Am going to buy a product or two from them asap. This hobby and especially this site is too damn much fun . Tweaks... and do they work?.... What do you think ?

I absolutely agree with Barry - I don't get anything until I eventually get a clue how it supposed to do what it claims. For me understading adds fun, this is not about money at all. So far I couldn't find clear enough explanation how vibration may affect well designed SS devices... so no isolation platforms nor coupling devices have found their place in my shelfs yet. Cables, spikes under speakers are quite obvious... Power conditioners - the funny thing is that the better designed the power supply of the component, the less effect AC tweaks produce. For some reason I haven't heard about so well designed components yet...
However, all this is not about savings, it's about fun, so I don't see a reason why not to buy and try even if it doesn't work? If it makes fun, consider it working!

i use anti vibration devices under my cdp but thats as far as ill go with tweaks.

mike.