With my 98 stock LS1 I see 5 PSI of boost, so far it's still alive (10'000 miles after the installation).

I run 36 lbs Bosch injectors and an additional fuel pump and I see 75% duty cycle @ 6000 rpm and an AFR of 12.5
I guess your fuel system isn't enough for the boost you are making (don't you have the 24 lbs injectors in the 2000 LS1?)

I also run a water/alcohol injection and the results are grate. It richen up the AFR, reduces detonation and cooles down the charge air.

This AFR was measured with water alone and a very low timing. With 50% alcohol (6 GPH) the AFR goes down to 11.5. At that point I can run 17 degrees of timing without KR. More timing or a different AFR didn't changed the performance.