The undershield has about 16 10mm hexhead bolts, and 1 pin in the center under the radiator support [I think]. This plastic panel is very light and flexible. More for underbody airflow management than anything else.

I've used 2x12 lumber built up to two levels with a small piece at the end for a tire bumper so I don't drive too far and off the "ramp." Used them for about ten years now without any trouble. It's not as high as steel ramps, but it sure is stable!

 

I've posted this before but here it is again:



"Dear Mr. Gallup,

Thank you for contacting Nissan North America, Inc. and allowing us the
opportunity to be of assistance.

I apologize for the delay in my response as we have been experiencing
technical difficulties.

Our 2003 Nissan 350Z was built and tested with mineral based oil. And
please remember that this is only a recommendation; you are more than
welcome to use your preferred motor oil.

If you have any further questions or comments, please feel free to e-mail
us.

Sincerely,

Trinh Nguyen
National Consumer Affairs"


Get some black plastic Rhino ramps at Walmart. There may be more than one height as some people have said they had a clearance problem with the front bumper but the ones I bought have an inch to spare .