HA! Nice pic, Tim...

You could also do a quick search of the Neon forums, Bill. I'm not familiar with the 420a setup, but you have several options. Some have T'd off the feed to the MBC, or close to the turbo, but this can result in inaccurate readings with spikes and surges.

I'd say your best and most stable/accurate bet would be to feed off a vacuum line coming right from your intake manifold to something small and innocuous like a solenoid. NOT the brake booster.