Is it safe to change your lug nuts to aftermarket ones? Coz i am planning to buy this http://www.ebay.com/itm/160665346225...84.m1439.l2649

 

Not on the stock wheels. The lugs are designed with the built in flat washer to hold the stock wheels in place, which have a flat base. To use acorn lugs like the ones you linked to you have to have aftermarket wheels. Most aftermarket wheels can use any type of lugs.