Cheap tweaks...What would YOU reccomend?

Haoleb, you asked above if elevation effects your sound and the answer is yes. At higher elevation there are less air particles and since sound is produced by the movement of air particles, your amps will be working harder to get your speakers to produce sound at higher elevations. This is more noticible in the lower frequencies since the lower the frequency the more air that needs to be pushed. I have not had any experience with this myself but one of my collegues ran into this problem. Of course when this happened to him it was in Mexico, City which is pretty high up there so the effects may not be as noticeable say around 2k to 5k ft.

10 Vibrapods of #5 under each Speaker.(200lb speakers) .
The speakers may wobble for a few days but will settle in . It really makes the tonal quality of the bass notes clearer.

Marigo Audio dots!

I can vouch for the Marigo suggestion posted above. I found that the Marigo tuning bands on the bass and midrange driver baskets produces an even greater effect than the dots on the driver cones. I would recommend both. Actually I have these things all over the place. Walls, windows, driver cones, driver baskets, etc. They provide denser images, greater detail, and greater dynamics.

Clean all of the RCA connections. There are several commercial products for this, I like alcohol (grain) and Q-tips. (disclaimer: I own no interest in Johnson & Johnson)