I bet the hub-centric rings will help with your vibration. Regardless, you should invest in a set.
I once had a 2003 Chevy pickup that I installed aftermarket wheels on (truck was designed to be hub-centric, wheels were lug-centric and did not include hub-centric rings). I was a 19-year-old kid who didn't know any better. I never could get the wheel/tire combination to feel like it was balanced, even though 3 different tire shops balanced them and said they were good to go. After about 5,000 miles, I made a right hand turn and heard a jingling on the road, followed by a loud bang and a scraping sound. 4 of the 6 wheel studs had sheared off. I found my lug nuts in the intersection with about 1/4" of stud sticking out of them.
On a hub-centric setup, the up/down/forward/rearward forces are designed to be taken by the hub itself, and the lug studs are only designed to take the side-to-side force to keep the wheel in contact with the hub. Running aftermarket wheels without the appropriate hub-centric rings exposes the lug studs to all of the above forces, not just those they were designed to withstand.
I was lucky with my Chevy, as I was only doing about 15-20 mph when those studs let go. It could have been much worse. The brake rotors/hubs on all 4 corners of the truck were showing signs of the wheels "walking around" on the hubs. I ended up replacing all 24 studs and sold the tires and wheels (to purchase a turbo setup for the truck...), with a new set of hub-centric rings.
2013 Billet Silver JKU Sport S, 6-Speed, TF Leveling Kit, Spidertrax 1.5" Spacers, 285/70R17 Firestone Destination M/Ts on OEM Sport wheels.