That is the card, however plenty of other 4GB cards seem to work as stated by others in this thread.
That card has one 6-pin and one 8-pin connector. I connected one 6-pin cable directly to each connector.
Yes, I used the MAC ROM in the thread. No extra PSU needed. Boot screen, yes.
As Dr Stealth posted already, the MAC ROM in this thread has reference clock rates. He used Kepler BIOS Tweaker to copy the FTW ROM values over the reference values in the MAC ROM. I ran at the reference rates for a while just to make sure everything was working, then I followed his footsteps and did the same.
So to answer your last question, yes full FTW clock rates, but that requires the extra step of using Kepler BIOS Tweaker.
I only changed the values to match on the common tab. Should I be doing something with the boost table too? I could take a look tonight and report back if there is something you want to see.