Yes, they are reinforced. I don't run them. I use FelPros. I'm on my 3rd UIM. I did the first one and lower gaskets at 77,000. The lower gaskets were complete junk. SEVERLY deformed.
I then had to replace my UIM gasket (leaking). At the time I opted for a Bob Dillon sleeved unit. That was at 115,000 or so. At the same time I pulled the lower to inspect my Fel Pro lowers and they looked brand new! I still replaced them anyway for piece of mind.
At 140,000 all gaskets and the Bob Dillon UIM are holding up well.
I will likely get back into the lowers again this summer/fall. She should have 160,000 by then.
Can't be too sure when it comes to the lower intake gaskets.