So if you're in Canada, that link won't work...defaults to Canadian main page and the Cdn site doesn't seem to have them. Looks like those come with studs and lug nuts. So are you using your OEM lug bolts to attach the spacer to the hub, and using the lug nuts they come with on the
wheel?
While they say studs are 12.9 grade, which is great, it is an unknown name and the spacers are not forged. I personally would not be very confident taking the risk with these on my vehicle, but that is just me. Trouble is, there are few quality hub centric spacers that are forged with lug bolts to fit our vehicle. However, we have the same specs as some Ferrari and Maserati models...go figure. Bonoss makes a really nice spacer, forged, with high grade strength lug bolts to fit our vehicles, so you can use stock bolts for the wheels as you normally would. But damn, USD$179 for a pair at 20mm, maybe cheaper on ebay. I would not hesitate getting the Bonoss for my summers, but don't need since my summer wheels are custom offset and flush. But not willing to dish out for my winter set just to have them more flush, which is what I was considering.
Anyway, although I would not do it to mine since I generally keep my vehicles 3-4 years, lowered looks great...not overdone like some pimped out vehicles.