Once you get to a point with your project that the stock ECM just won't do the job, it is time to get serious and install a total ECM replacement. Don't even think that a piggyback will get you by because it won't. Learn from my mistakes!
I basically had two choices that were within my price range: Haltech (~$600) or Megasquirt (~$300).
With the MegaSquirt, I would have to build it and tune from the ground up, which was very appealing at the time, but time was against me. I decided to buy a Haltech E6GMx from a friend for $600 because it was such a good deal and would save me some assembly/installation time.
Gettin it installed was a snap and only required minor rewiring on the harness.
On the wiring harness-
From -> To
C15 -> D16 (injectors)
Ground D3 and D10
A2 -> C2 (A/C controller )
Go into the main setup and go down to aux/out function, change the setting to ign/bypass.
Make a jumper to go from the 5v output on plug 2 pin E4 or E5 (be sure it's plug 2) and connect t-tap that to the EST bypass control on pin D5. If you don't t-tap this in, you'll be stuck at 10 degrees and have over heating problems/lack of power.
trigger angle 100
trigger edge rising
output type - constant duty
output edge - falling
switch setting - 30%
The two 3 pin connectors on the harness near the communications connector, one of them will have these two wires:
'Trim' input: red wire w/black stripe.
'Spare AD' input: Green wire (center wire) - This is the one I connected the Wideband data wire to.
For data logging with the AEM UEGO wideband, I set the calibration screw to P02 (Position 2 is linear with a voltage range of 1-2v).
The Haltech will log only the voltage, so you can use the following calibration, 1V = 10:1AFR, 2V = 20:1 AFR.
Now when you view the voltage on the Haltech, it will resemble AFR (so a voltage of 1.25 would equal 12.5 AFR).
If you wire it to the Spare AD connection, you have to select 'Spare AD' to log.
The log value displays the voltage as 1250.000, so you mentally have to move the decimal over 2 places (12.50000AFR)