How do you get the right wheel offset" If you want aftermarket wheels, either 17x9 or 18x9, how do you know you're not gonna end up with something that sticks out? I don't mind flush or factory offset, but I don't want bro wheels. I'm thinking 35" tires on a 1 or 2" level kit.

 

I asked Tire Rack and they didn't know the factory offset. Once you know that, you can compare to the specs on the aftermarket wheel.

 

I read in several spots that the factory offset on the 8” wide wheel is +40.
There are some pics on here of 0 offset or +1 on 9” wide wheels. IMO the wheel is pushed out too far beyond the fender. I think +20 on a 9” wide wheels is where it needs to be

 

+40 is factory on the 8" wheel. I have had 0 offset before and it sticks out quite a bit. I may go for aftermarket 18's at some point, but they will be +20 or +24 whichever I find.
I don't recommend 17's, I had them on my '16 and never liked the tire choices vs 18".

I will try to explain +20 on a 9" wheel vs the factory 8":
Difference of negative 20mm offset,
1 more inch of wheel width is 25.4mm, 12.7mm in towards suspension, 12.7mm out towards fender. So a +20mm wheel will stick out the 20mm plus the 12.7mm for a total of 1.29" further out towards the fender vs. the same tire on a stock wheel.

Here is a 285/70/17 17x8" zero offset wheel on my '16:

 

this is a good site to compare sizes

Custom rims, wheel tire packages for your ride - RIMSnTIRES.com

 

I don't doubt you, but I went with an aftermarket +20 and I don't believe that my tires are sticking out 1.29" further. Only looks like I picked up a half inch or so. I love the +20, because my 37s (with 2" level) still fit flush with the fender.......and look great