Long time no post.
Just an update:
Dumped the V and got into a 2011 Yaris 5 Door Hatchback (5 Speed)... no more creaky air vents, whistling engine, rattling/loose driver's side window - all normal according to the Nissan dealership.
For my first tank, I drove it to 429 miles before the 2nd to last fuel bar disappeared. Filled it up and it took 9.86 gallons to the first click.
On my second tank, I drove it to 418 miles before the 2nd to last fuel bar disappeared. Filled it up and it took 9.66 gallons to the first click. What's amazing is that on my second tank, I had my GF in the car for a total of 130 miles. She's 135 pounds. And then I had my friend who's about 190 in my car for a total of 140 miles (mini road trip). I was also stuck in bumper to bumper traffic for a total of 35 minutes.
Anyways, once I put Mobil 1 up in there and after about 10K miles, I should be able to get 50+ highway.