yeah there needs to be a sticky. But I find that if you actually spend some time and do some searching you will find the info you are seeking...
If you want to get the bolt on type spacers on stock rays 19's you will need 20mm in the fronts, otherwise stud replacement 15mm will work fine. (issue is the built in studs will hit the wheels, there is no hollow area behind the wheels like on other wheels)
You can go 20mm in the rear no problem or even 25mm if you are daring.
If you want to do it yourself and save $, and also have the opportunity to go back to stock easily, get the 20mm bolt on types and be done with it.