So my city has been snowing really bad lately, as I was doing a turn, I think i hit something under my car and heard a loud bang. Afterwards, my whole car begins to shake including my steering wheel. When i came to a complete stop it became fine again. As soon as i accelerate up to about 60-80 kph, my whole began to shake again. Do you guys think it might be wheel balance or it might screwed up my wheel alignment since i hit something really car. PS. My car is lowered. Thanks for all the help!

 

Yes. It sounds like you jacked up your alignment.

I'd get it aligned and re-balance the wheels. That should do it.

 

For starters, you have a bent wheel.
You'll need an alignment check to see if anything else, like a steering knuckle, or lower control arm was bent in the impact.

 

Could also be a bearing issue.

 

I bought my 09XS sedan in April and noticed my passenger seat would shake at around 65MPH. I just got an alignment and balance and it's still happening. I heard the Maxima's had an issue with the same thing and they came out with a bearing kit the dealerships could apply. Anyone know if this is a known issue and if they came out with anything like this for the G37 sedan?

 

tires, alignment, bent wheel, or balancing.

 

As tvpost said, i would think it's probay a bent wheel. It could also be a bent rotor (usually caused from not correctly torquing the wheels).

 

Get it repaired. Move out of snow country. Enjoy life.