I had a line on a set of brand new 2010 OEM GT 500 take offs... and test fit them on my 03. The wheels were 18 x 9.5 and the backspacing is more than the new edge.
The rears tires are 285/40/18 and fit great with a 1.5" hub centric spacers. The front tires are 255/45/18 and I tried 1" spacers but had rubbing issues on full lock. Tried no spacers up front but the high backspacing didn't clear the brakes. With 1/2" spacers on it was close... but at full lock it touches the front shock tower. Overall the 1" spacer was the closest. If I went with a shorter tire then the 255/45 I think I could get it to fit - but it will be close.
I went a different route in the end. I do like the look of the OEM GT 500 wheels on the new edge - but I'm not a fan of the chrome knockoffs.