Cheap tweaks...What would YOU reccomend?

I've done two cheap tweaks that dramatically improved my system lately.

1) elevating my amp by placing a phone book beneath it.
-There is a night and day difference in bass extension. The bass is flat before the presence of the phone book. After, the bass is more deeper, controlled and permeates the room in an almost waves like manner.

2) spent $40 bucks purchasing 2 sheets of Dynamat Extreme from Carmedia1.com and tacked it on the bottom of my shelves. This transformed my shelves from a "scat scat" to a "thonk thonk" when knocking on it. The aural improvement is equivalent to swapping to slightly higher end power cords in the digital front ends.
-The highs and "digital" harshness is tamed a few degrees. Before, the highs hurt my ears if I played over the "55" setting on my digital preamp for over ten minutes. After, I can play up to "65" without ear fatigue.

any suggestions or feedback on upgrading speaker jumpers?
Any brands better than others?

Recommend a good set of cones along with some pods. I bought some from this website (can find them anywhere else) ....... audiolabtc@aol.com..... These cones really work as isolation devices and they are fairly inexpensive (improves bass defination, detail, and resolution on a component).

Speaker tweak: If your speaker is under 7-8k and for many more expensive. Upgrade the caps in the tweeter signal path. If you are really ambitious measure your woofer specs and retune your cabinet to it for max performance with flattest response.

Sincerely, I remain

Connect the 4 outputs with one channel split of my cd player and connect it to the external 5 channel in on my receiver. Sounds much better than the 5 channel stereo DSP.