Yep, I cut extra holes in mine for better air flow and cooling.
The thick (top) end was "dummy" with hatching but no holes.
I removed the vents from the car, got the Dremel out and attacked the top ends of the vents.
It was hard to get a smooth cut and the edges are still a bit rough but no-one but I will ever know.
How much difference if any it made to heat evacuation is anyone's guess!

 

We must have similar OCD, because that's exactly what I did. Difference? I dunno. I'm sure that resting, heat escapes to reduce soak, but I'm not sure if air flows in or out when at speed. It depends on how far forward the typical high-pressure area at the base of the windshield extends.

 

I just actually polished a few pieces on my car and learnt some lessons... These "polished" plastics on our cars can indeed be polished, but they don't actually have a clear coat. It's just a hard plastic surface. More so, there are two types on plastic on these parts. The first is a harder dark, shiny, polish-able plastic, and the second below that is a somewhat foamy plastic. You obviously don't want to go too aggressive with the sand paper or you will burn through the first layer and there's really no point of return. I don't believe you can even paint over it as the second layer of plastic somewhat crumbles.

You can see what I mean below. This is the lower piece on the front bumper that's either gloss or satin black depending on your spec. Mine was full of chips and scratches, so I thought I could sand them down and finish it off with some polishing.



I would advise you to wet sand with 3000 grit, then polish. No more aggressive than that!

 

 

Which piece? The lower portion that I mentioned? If so, I totally would if it was a new gloss piece, but I'm wrapping it in gloss black 3M for now.

 

Yes, that's the piece. If wrapping in gloss black, that will give you the protection as well. I went the other way. I wrapped the gloss black splitter with matte black.

 

Come to think of it, it doesn't make sense to wrap any of these pieces professionally. I wrapped these myself so the cost was just the vinyl, but I got a few quotes of $150+... a brand new piece straight for Jaguar runs $200. I'd rather replace the thing whenever it get's too chipped as opposed to wrapping. Plus, very few wrap jobs actually come out flawlessly. Flawless isn't an issue when it comes to factory parts.