Tom,
Looked like there is no recommended shops for "Zs" in the area, so my next best option was Corvette Connection (one of two Vette specialty shops in Denver). I was told that the mechanic was familiar with the LT5... to be safe, I sent them the following links in a *tactful* email:
http://www.zr1netregistry.com/plenum.htm (plenum removal)
http://www.bcvettes.org/ (step-by-step under how-to)
http://www.zr1netregistry.com/ZR1_issues.htm#10 (adding add'l drainage)
I'm keeping my fingers crossed... we should find out in a week or so.
Another good reason to get a manual and do it myself.
Scott