Yes - sarcasm. Literally the very first TRD Pro skids were on KDSS 4Runners (the first pros had KDSS on the pre-production ones).

You have to cut the sides out. Dozens of guides can be found with a google search. It's easy and you can do it with a jig saw in about 15 minutes.

The down side is that it's not very strong. I broke mine on the first off road trip (crushed the center of the bottom and broke the welds on the sides). It actually held up worse than the OEM steel one. So I wouldn't expect it to work for rock crawling duty. But it's visually a bit nicer IMO. If you can weld in some gussets you could improve it a lot with a minimal amount of internal bracing and it would probably be really durable. It just doesn't have much internal structure.

I designed a replica in steel. If you have a fab shop or your own fab equipment I'm happy to email you the DXF file to cut the template and then you can weld up a steel version that will be a lot stronger.

Good luck.