Back already with your info.

Turns out the 928 shop actually sent his block to US Chrome for Nikasil plating and honing:

US Chrome Corp of Wisconsin
650 Oak Park Ave
Fond du Lac, WI 54935
(866) 922-5066

As for Diamond Racing:
Diamond Racing
Ask for Nick ([email protected])
+1 (877) 552-2112
(OEM Replacement design should be on file)

Hope that helps; feel free to email me direct if any further questions about the build...

We also found a very good machine shop in town, eventually, for the balancing etc... not sure where you're at, though - please add your location to your profile!!