I am currently in the research phase of setting up a Mbuna tank (sorry if i spelled that wrong). So far, I've got the fish picked out, their diets hammered out, I know about cycling, and I have also looked into compatability/cross breeding issues. My remaining quesition is about the water requirements.

I know African Cichlids prefer high pH, high KH and high GH. My tap water comes out of the tap 9+ (off the charts), but drops to 7.6-8.0 within a week. GH is around 4, and KH is also around 4 (dipstick test, not liquid based like pH and GH). Should I try to alter my water to increase the KH and GH or leave things alone? If so, do you have a recomended method?

I would add crushed coral to a filter to act as a buffer so that the ph might swing so fast.

You could also use arogonite as a substrate. :)

It will be much more important to have a stable ph then a ideal ph value

How should I stabalize it?

Stability in pH comes through high gH and kh...AKA "Buffers"....adding crushed coral to a filter, or aragonite can help to buffer the pH. You can also buy commercially availble "African Cichlid Buffer" that helps to keep your pH stable...I use SeaChem's Malawi and Tanganyika buffers respectively....