Specifically, for the ECU / engine wiring harness?
I bought the subscription to the http://www.maseratitechinfo.com/ book store, but it was short on information.
If anyone has the info, PM me and I'll give you my personal e-mail address.
"Short on information" is an understatement! Not a single useful tech document there. I asked for a refund. I had mistakenly assumed that, like the Nissan/Infiniti tech sites, there would be detailed shop guides/manuals available. Nope.