I just did this repair at the beginning of November and thankfully my wife was almost home when one of the tees went. I took the tray off the firewall to make it easier to get to and got the oem tees from the dealership and replaced both. I figured I was better off going with the oem tees rather than metal. I was curious about the old tees since they looked strange and not like real plastic in their deteriorated state. They looked like they were formed with cellulose in their construction. I asked the person at the parts counter at the dealership since I was concerned about debris in the cooling system and they spoke to one of their technicians and they didn't seem to think it was an issue. They almost look like tthey're designed to deteriorate since not all of them was left when I pulled them and their parts out of the hoses. Since the old ones lasted for over 230K miles I figure I won't have to worry about replacing them again.