So you car has the following stock wheels with the following specs
18.0 diameter
7.5 wide
50.5 MM OFFSET
67.1 CB ( center hub bore)
5 x 114.3 MM stud pattern. 5 studs on 114.3 MM bolt circle diameter. Also 5 x 4.5”.
114.3 MM is the same as 4.50”
The diameter and the width are pretty straight forward.
Offset can be positive or negative, however almost all wheels on modern cars have a positive offset.
So offset is the distance from the center of the rim to backside of hub, (spokes)
On your wheels if you drew a line down the center of the rim top to bottom the back of the hub is offset 50.5 MM (1.99”) toward the outside of the car.
So you looking at wheel that has an offset that is 45 MM (1.77”) so if you subtract 1.99- 1.77 = .21”
So since the offset on the new wheel is less the wheel will stick out toward the outside of the car an additional .21” which gives it a wider more aggressive look,
This is if you use a wheel that is the exact same width of 7.5” of your stock wheel. If you buy a wheel that is 8.0” wide, you have added an addition .50” total width. So it will be .25 wider per side.
Now add .21 less offset and .25 additional width and the wheel will stick out a total of .46 wider toward outside of car.
Now the other thing you need to know is the center bore diameter of the new wheels you at looking at.
The center bore is important as it fit the hub of the rotor and provides centering and support of the wheel on the vehicle,,so the studs do not have to provide all the support and also makes the wheel run true.
This Is the the little round hole in the center of the wheel. Yours is currently 67.1 MM CB
As a example, allot of aftermarket wheels have a 74.1 MM CB.
So in this case you would need to buy a hub centering ring that is 67.1 to 74.1 conversion
(eBay $12.00 for all 4)
Remenber this is an example ., you need to vericy the the size of the wheels you buy.
Last but not least, you will either have to have your TPMS wheel sensors transfered from your current wheel to you new ones or buy another set.
Now to answer your question directly. You can install either 19 or 18 wheels with 8.0“ width and 45 MM offset and will fit fine and look good. I am looking at upgrading mine to 19 x 8 45 MM offset
Final note make sure the new wheel have 5 x 114.3 bolt pattern
Good luck and hope this does not confuse you. Most people,do not understand all the variables when looking at wheels.