Well, I learned a lot over the past couple days.
1. Very strange things happen when the boost gain is raised to very high (70-80) levels on the UTEC. Boost flutctuates like crazy.
2. The GM solenoid is VERY sensitive. Making small changes to boost gain means you have to make changes to your boost map as well. This was somewhat the case with the stock solenoid, but the GM is sensitive.
3. The GM solenoid is awesome and provides incredible boost control, if properly setup.
What worked for me:
GM Solenoid installed with new vacuum line (interrupt mode)
10 ohm 1W resistor
Vacu-tite vacuum restrictor between the turbo outlet and the BCS
UTEC boost gain value of 50 (I think I can go lower)
UTEC boost map value of 290 in the entire 100% column for 18psi (I had to fluctuate values with the stock BCS to get steady boost so this is nice)
What did not work for me:
No vacuum restrictor. Big spikes and fluctuating boost.
Boost gain values greater than 60. I got very unstable boost with high values, which is strange (at least on the stock BCS). It seems the GM one is so much more responsive, if you give it a chance to work quickly, it performs very well.
With a boost gain value of 50, my boost curve climbs quickly up to 18psi and STOPS. It then holds 18psi in a perfectly straight line (I have never seen this in Data Log lab before!) for a couple thousand RPM then slowly climbs to 19 psi after 5000 rpm. I think I have to slightly decrease my boost map values after 5K. The stability of boost is incredible!
Thumbs up in my book but you need to be careful tuning it, it is very picky.