Don't b****, I did search the forums.

Do we need the engine undercover splash shield? I get the argument of debris flying up in there, my Honda Accord had 276,000 miles when I retired her and she did not have any shield. Someone mentioned airfoil dampening? Which to me sounds silly.

There is a guy selling aluminium fab replacements, but, is it necessary?

You don't have to have it but may find it difficult to keep all the lower plastic panels in alignment without it. It keeps debris, water, mud, etc. from getting all over the place around the engine compartment and does a good job at it.

I actually replaced all of the bolts with new stainless, and put it back on. I was looking at the bottom and you can clearly see how something like a rock can kick up and knock that oil filter, or get into the belt, wet the alternator, even gash the radiator.

Replacing the bolts is not a bad idea. I learned quickly that the first time you remove one of those bolts you should put anti-seize on them upon re-installation or it will rust to the clip and you can tear the plastic getting it back out again.

An aluminum undercover shield is a bit overkill unless you do some off-roading.

Try a company called TBW. They have an aluminum splash shield that has a door which allows easy access to
the oil filter and drain plug by removing only two screws. Makes oil changes a heck of a lot quicker and easier.
It is a two piece splash shield so you can remove it all, or half depending on the need. I put one
of these splash shields on both my '04 350Z and my '14 Q60S. Beats the d!ck out of removing all those screws and that shield every time you change the oil. You can run the car without the shield, but I would
not recommend it. These cars sit real low, and are real wide. You will end up with a ton or road dust and debris
up in the engine bay. Plus if it rains, you don't want water splashing up in the engine bay, considering all the electronics in today's cars..

Yours and do as you will of course but I remove mine off of new cars to see any leaks quick which can seem to disappear with the covers on. And less work changing filter. Of course rocks and such can hit things but they always could and never had damage yet in 40+ years. The covers gone do not affect cooling in the least, they are mainly for gas mileage and such a small amount they can easily be suffered when missing. The covers in place like here in Texas can easily cook wiring harnesses and plastic parts faster by trapping in heated air during the summer.