Torx patent
https://www.google.com/patents/US3584667

I will say that after doing the oil cooler seal job on the OM642 it made me a believer in the E-Torx screw heads. Much more secure connection to the tool and it is darn near foolproof.

When you are working on a bolt that you can only access with a swivel joint on the back side of the block it really makes a difference.

The best advice I can give is to use Lisle sockets not the Chinese copy ones at Harbor Freight. Search on Amazon, the Lisle E-torx set is on the order of $20-25 or about double what you pay for a set at HF. US made and worth it.

Lawsuits were filed against General Motors over people having to take their vehicles in to the dealerships to have headlights replaced when they (GM) first started using torx screws, , ,

Torx patent expired in 1991 and phillips in 1996...

I hadn't heard of that but anything is possible when someone wants to ( try to ) generate business for their law office. Anyone can bring a suit for any reason, prevailing is another issue.

Any links to the actual case and results?

A Phillips requires axial force while the screw is being run in, a Torx does not making to less prone to stripping.