I took my car for an oil change...damn mechanic forgot to screw the protector shed back on tight and cause it dragging and tearing.
My question is do I need one or Can I drive one without it? Does dealership carry it?

 

you dont "need" it but its there for a reason .

p.s. your mechanic should pay for it .. imo

 

Make the mechanic pay for it; it's obviously his fault
You don't need it, but it's there for a reason (undercarriage aero) as Rider said
You have to get it from the dealer
You need to find a new mechanic or better yet, do it yourself

 

Does anybody know what this part call anyways?

 

under body cover

 

^+1 it was his screw up

 

I would call it a plastic splash guard. But as they said on some vehicle it works with aerodynamics such as BMW. Ur mechanic should pay for it!!

 

works the same for our cars ^^

 

I think it's called the "lower engine cover". It's gonna cost your mechanic about $200 to get it new. (call everythingG35.com and give him the cover AND the bill) Yes this cover is important, first, it keeps your engine compartment clean, second it controls the air flow under the car to stabilize it at high speeds.