I contacted Cal Pony Cars about the 20" wheels they had at SEMA. (the ones that were made to look like the '65 Styled Steel Wheels)
I asked if they planned on making a set in 17's or 18's for the '05. He said all they had were the 17x8's for the pre-05 Mustangs, but they had some pics of them mounted on an '05.

The guy that sent me the pics (Frankie) said he wanted to see what the response would be if I posted them, so here they are. (pretty impressive that someone in the aftermarket actually wants to hear opinions on their products)
Frankie said the tires in the pics were the original sized OE tires. (235/55/17)

I don't know how much they cost, but he said they were less than the 20's and those run $395.00 EACH.

EDIT: I saw in an old post where the 17's were $350 each.

 

Those look pretty slick!

 

Not for me.. I like retro, but those look way too small on there. 20's may look good, but not 17's. 18's may work. And that's funny, because I typically prefer 17's and 18's. hmmm.

 

IMO, they're perfect in the 17s. Anyone know how much they weigh? They look hot on white w/ blue stripes.

 

Those look much better than the 20's imo, but I still don't like them.

 

maybe if the demo car was lowered it would look better but i have to agree an 18" wheel would look nice or 20"

 

I agree with Ira.

 

The 17" wheels don't look so stretched out like the 20" wheel does. Even if they lowered it with the 17's it would look better than the Hummer stance the photo shows.

 

I have the real thing on my 70 Mach 1. They could have made them look alot closer to the real thing. Just not quite right.
Scott

 

They look much better than in 20", I agree.
I just don't know if I like them on the S197, I think they are "too retro". In general I don't really like the look of the chrome rims on the new Mustang, which is all painted on the outside. They did look great on the old models that had more chrome parts (bumpers, trim, etc.).