I don't think the No Limit ones are the same as Beans, they are flat like Riff Raff.
I have been reserching plenums since I'm getting serious about changing to a T4 turbo.
I found the Beans ones on their site but it was not easy. Like they don't want to sell any or something!
I'm still on the fence between the possible (perceived) benefit of plenum volume and possible air flow improvement and the simplicity of o ring sealing combined with less issues with clearance of hoses and lines and no possibility of interference with any future turbo.
I may just put some inserts in some stock SD plenums and be happy. It isn't the money, it is the actual benefit.