I know the OEM wheels are 8.5 inches wide, I have been drooling over the Forgestar's in the 19x9 pattern (so I can rotate and balance), but would you notice a handling difference in just a half inch?

 

Unless you drive around traction limits, there is no difference.

 

95% of people are confused about wider wheels. It's the tire make up that gives traction. Put the same tires on 2 identical cars, one with wide tires and wheels. Wide one will have slower acceleration, longer braking, hydro plane in water easier and cost more.
Most that get wider tires see less tire spinning for 2 reasons
1. Picked a better tire when switching to wider
2. The heavier tire and wheel is eating up power
The only benifit for some is the look which is something I never notice on a car.

EDIT:
Oh I miss read, you mean same size tires but with a wider wheel because they don't make the 8.5 width. My bad, ya that's no problem

 

Putting the same tire on a 19x9 compared to a 19x8.5 you won't notice any difference unless one wheel is drastically heavier than the other...

 

^^
What he said.

 

Thanks guys.