The armrest is an OEM part - appears to be very sturdy - I would not expect it to sag and it's identical to the the leather in the rest of the car.

The dealers eBay id is pricetoyota_scion I'm sure u can search for his store - He is a Toyota dealer. He also gave me permission to post his store id. He didn't show the armrest on the site but responded quickly to emails. I believe he can obtain any offical Toyota part u need.