Before you waste any more time/money on replacing parts (unless of course they need them) try to isolate the vibration to what part of the car it feels like. I will list a few short ideas. Also, I don't know how likely you will be to find one of these but back when I worked for a dealer we had a vibration detector that would pick up the tone of the vibration and display it like an occilator. The wave length of the vibration almost always was able to pin point exactly where the issues was.
Try,
1) when you get to middle range of vibration territory toss the car in neutral. That will eliminate or isolate any engine/trans issues.
2) Do you feel the vib in the seat of your pants or in the front end. Front end means steering components/wheels(no such thing as rims, but wheels do have rims on them!!), seat of the pants means driveline or rear wheel issues.
3) If you have someone who can ride with you, have them weat a mechanics stethesacope and "seek" out areas that are louder. Of course sound travel easily but will always be coming from the loudest area.
4) Last but not least.....run the 16" wheels and forget about it....

Good Luck