Decent handling susp setup?

Well, 17's definitely have a better tire selection than 15's, although even at 17" there's a lot less choice than there used to be. With a 17" you can go up to about 5.6" of backspace on most rims. That limits you to a 17x8 or 17x8.5, and would let you run up to a 255/45/17.

There was at least one member here, Duster346, that had a set of 17x9" Cobra R wheels on his car, they have a 6" backspace. He ran 275/40/17's, but later told me that he was on the fenders and the tie rods, very little clearance at either location. I didn't find that post right off but I know he said he basically had no extra clearance anywhere. Which makes sense, with the 275/35/18's I run I'm basically right at the fender and the frame, so, you can't go bigger anyway without significant fender mods, at least not on a Dart/Duster fender. The Barracuda's seem to have a little more room. I have 6.1" of backspace on my 18x9's, so, in theory he would have had less fender clearance but that comes down to tire manufacturer at that point. My tie rod clearance isn't an issue with the 18's though, I've got plenty. Not sure what it would look like with the cobra R's, it has to be tight

Here's his posts
Anybody running 17" Cobra Bullit rims on a Duster
his build thread for the leadfoot rally
Leadfoot Rally '73 Duster

So what that means is that if you wanted to run a 17x9 it would come down to rim design, and you'd basically be buying a rim hoping it would fit. The Cobra R's are the only 17" rim I've heard of that didn't interfere with 6" of backspace. I'm sure there are others, but, it would be on you to find them. By comparison, a set of 17" bullit rims won't fit after about 5.6" of backspace, the factory Bullit 17x8's with 5.72" of backspace all need a small spacer for tie rod clearance (there's a bunch of folks running those). To run a 275/40/17 you'd need to have 6" of backspace, any less than that and you'd be into the fenders for sure, any more and you'd be on the tie rod ends. I think the best case would actually be a 255/45/17, running it on the 17x9" would improve the tire/rim fit since a 17x8" is the minimum width for that tire. And with a 255/45/17 your backspace could be between ~5.6" and 6", so you could actually use spacers to modify the tie rod clearance if you had to. With a 275 you'd basically just be stuck if it didn't clear the tie rods with a 6" backspace, you'd have no room to the fender to add a spacer to improve the tie rod clearance.