Dragging the gas tank - 98 Convertible

[svicars]

I'm a new Mustang owner (just over a week). I bought a used 1998 V-6 Convertible off a dealer lot. Car runs great except now I keep dragging the gas tank when pulling into parking lots or especially when making a right hand turn onto an incline.

I've now figured out that the aftermarket wheels and tires are not the right size. I'm not sure how wide the wheels are, but they are 16". I'm running P245/50 R16 tires. Normal specs for the car are P205/65 R15.

The front tires are rubbing against the sway bars in front when I turn the wheel all the way to the locks.

If the tires are a little shorter than spec, could this be why I keep draggin' my tail?

As far as I can tell, it looks like stock springs & shocks in the rear.

The plastic cover on the gas tank is all scratched up - it's been dragging for a while.

Any ideas?