LQ9 Engine

[HEEP]

Found another engine from a local guy. He thought he was selling me a LQ9, however, it turned out to be a 4. He said he would make it right and has been looking to find an actual 9 but has not found one. His offer was to find a 9, pay for the tune on the 4, or give me my money back. I chose for him to find a 9, but he can't seem to find one.
In talking with him today, he said he is still looking, but stated that I would probably not notice a difference between a 4 and 9. I also asked if we could go LS1, and he said that was up to me. So, I ask the professionals here, what would you do.
I have no fear that this guy is trying to cheat me. He has kept in touch, and answered every call I have made to him.
So, need some advice here.

Thanks,
HEEP