On my 07 the shield got hit while on the highway with something, Was hanging down a bit and one day at the grocery store with the cement parking stops it finished the job. I have been running around for a couple of months without it and no issues. I tried ordering the Chinese E-bay replacements with the same part # but I had to return as they just don't fit correctly. Do I really need them?? On the local Lexus dealer website I see they have them for $195 for both. Big difference in price. I believe I paid like 80.00 for the copies but you already know the outcome. So, are they necessary?

 

Not necessary, it actually does not cover the engine, just the front of the engine.

 

Mine got beat up also! I removed it, epoxied the breaks paint and put it back. I don't crawl under the car anymore so it's all good for me.
Ed

 

Its preferable to have them. Keeps water and dirt out of your engine bay and getting onto things like electrical components. Check junk yards for pricing. You could also repair your old ones if you still have them. I know a guy who built his own out of metal for his BMW. BMW fully covers the bottom of the engine bay, so very little gets in or out. Lexus is only a partial cover.