VAM problem

Unfortunately I cannot be of much help there, but I would recommend either doing a MAF conversion or switching to speed density. The VAM is a restriction on the intake, it makes your turbo work harder to get air. Even doing the blow through, it is restrictive, and moving away from it is a better option in the long run if you are trying to get more power. The MAF conversion requires over riding the stock programming, which you have to do for a blow through VAM if you want reliable results anyway. A MAF produces far less resistance to flow than a VAM. the 90mm lighting MAF is a good choice, then you need the connector to plug in. You should be able to find instructions on the conversion. Then you can run a Jaybird or Quarterhorse on your stock ECU to allow it to interpret the new signal correctly.

The speed density doesn't use the VAM or a MAF, but rather uses a MAP sensor to measure vacuum or boost, and combined with RPM, intake temperature, throttle position, and known constants (injectors size, displacement, and a custom made fuel and timing map), allows the computer to calculate how much air the engine is flowing, and therefore how much fuel the engine needs. No restrictions, and overall, for performance purposes, is better than a VAM or MAF.

Unfortunately, I don't know about the spring position.