I've got the symptoms, do you have the problem? (Vibration issues)...
 

Recently my car has been vibrating excessively, and I just don't know what the problem is. I think a key factor to this is that it occurs when the car is stopped and grows worse with speed. So if you are going to say it's a rotation problem (bad tires, bent wheels, bad bearings) I HIGHLY doubt that (especially since I had my tires rebalanced, wheels straightened, and new bearings put in 2 weeks ago :D). The only thing I can think of is the FSB bushings or motor mounts, and I swapped in my OEM FSB bushings a few days ago (and have had no differences). What do you suspect my problem is and how hard would it be to fix?
Much appreciated,
-Cyrus

If you pop it in "N" when stopped does the vibration go away. It might be your motor mounts.

Also make sure to check you wheel lugs are properly torqued. That was the problem for me once.

No the vibration doesn't go away.

Hmm.. that could very well be the problem since I tighten them myself and don't use my torque wrench. What should they be torqued to? And should I tighten them when they are fully on the ground or a little bit off?
Thanks for your help,
-Cyrus

Could it be misfiring? Misfiring feels very rough at idle and sometimes worse with speed where a lot of power is missing. Sometimes it is difficult to notice but if you look at your exhaust, it will make a sputtering sound and be visibly shaking whereas normally it purrs and looks stable.

Nah, I'm pretty sure it's not misfiring since it sounds so normal. But I will check tomorrow just to make sure.
Thanks,
-Cyrus

If the vibration is happening when you are stopped it's something to do with your engine and nothing to do with your lugnuts or suspension. Get your engine mounts checked.

FWIW, your lugs should be tightend to 85lbs in a criss cross pattern.

Oh great.:(