Porcelain Tower Question

Quick question -

Does Porcelain Tower wonder improve existing Research Agreements or only ones created after the tower was made?

(wondering if I should save my Great Engineer for it, since I am getting Architecture technology 1 or 2 turns before 2 RA's finish)

You get the PT benefit from any RA that completes after you finish PT (even just one turn after). So sign up the RA and finish PT before the RA finishes and you're in good shape.

Thanks - I was going to ask that question too

Thanks man