I've seen this Rock Sliders

http://lucky8llc.com/Products.asp?ProductID=2140

They seems pretty sturdy and well made

Problems, maybe a bit expensive, but probably worth it if you do a bit of offroad and they are located in the USA, so shipping adds a bit to the price.

Is there anything similar available in Europe? '08 RRS TDV8
I converted my diesel RRS to run on an environmentally friendly mixture of caribou fat and baby seals oil

Not sure if Uncle Ray on the D3 site makes them for RRS, but I'm sure he could! Porsche Cayenne S Diesel 66 Plate

That is way too much money for rock sliders... They are clearly marked up because they're for a RRS.

Those in your link are made for a forum member over Stateside who seriously offroads his Sport and has done since it was delivered. The high price is because of very limited production IIRC. He and Umbertob posted some fantastic videos of 4 wheeling expeditions in Arizona and Colorado in their Sports back in the very early days of this forum 2020 Pangea Green 1st Edition D240 New Defender 110 is here and loving it
2018 Melting Silver Mini Countryman PHEV - soon to be replaced
2015MY Corris Grey SDv6 HSE Dynamic, the best car I have ever owned, totally reliable only a cou0le of rattles in 3 years, now no longer in my care
Also in my garage is a 1996 TDi300 Defender 90 County HT made into a fake CSW

Have seen these in the flesh, very robust and well constructed. The slider actually extends well under the car so not only are the doors protected but most of the underneath as well, including the air compressor, but the soudproofing has to be removed from this to get them to fit, so is a little noisier.

The downsides are weight, lower ground clearance and expense. Shipping to the UK around £700 quid due to weight.

Unable to find anything like these any where else. Know someone did approach them to make them under licence in the UK, but not interested