Well I tried the above PPF, matched the MD5, burned & installed with NO via driver this time (but with the NEW nforceataTEST.kext that wasn't there before) and WOW did it install faster.
I'd say at least 40-50% faster then the pre-ppf'd disc in the exact same configuration.

Sadly however, no combination of rd= or other flagging can get past the waiting for root device again on boot from the sata HD...