18's and hub centric rings?
 

Hey Guys,

My rims should be here any day now and I was wondering if it is necessary to get hub centric rings. I ordered Exel Bk-7's 18x7.5. I did a search and some of member say it will decrease vibration. Please let me know. Can I get them at Pep Boys? This is my first set of rims, so I don't know much about mounting them.

Do I need to get a new alignment? It's coming with the tires mounted and balanced. I figured that when they get here, I can just take off my stock rims and replace them with the new ones. thanks in advance!