From the photos, the Compushift case looks rugged and is factory sealed.
Plenty of folk are running a fuel injection/ignition ECU on competition vehicles so no different with a transmission controller as long as wiring is done reliably.
Compushift Manual is here:
http://www.compushift.com/files/manuals/compushift.pdfDave/Ian Ashcroft: If you're reading this, would you be able to give an idea of pricing?