Nice cars!
As for the pictures - get a tripod, like now.
Set the White Balance to Tungsten for parking lot lit like that at night. Try the ISO at 800, with the 1600 the pictures are looking a bit noisy.
Try using the P mode where the camera sets both aperature and shutter speed for you, but not auto so there won't be any flash. You don't want to use that pop-up speedlight for these shots. Pay attention to where the camera sets the shutter speed and aperature and use that as a guide of sorts and switch over to Manual like you were using.
Hope that helps a little.
As for the pictures - get a tripod, like now.

Set the White Balance to Tungsten for parking lot lit like that at night. Try the ISO at 800, with the 1600 the pictures are looking a bit noisy.
Try using the P mode where the camera sets both aperature and shutter speed for you, but not auto so there won't be any flash. You don't want to use that pop-up speedlight for these shots. Pay attention to where the camera sets the shutter speed and aperature and use that as a guide of sorts and switch over to Manual like you were using.
Hope that helps a little.
