MG_MR2
That's interesting. From what I've read air needs to be able to bleed out so if you use a check valve, you would also have to install a bleeder valve that will let pressure escape
I have read the same also - I have read multiple opinions online saying that you are best off using the Toyota OEM part and not cheaping out. Is $50 really worth it in the long run?
However I will note that my VTV broke while I was doing my valve cover gasket (was soft and brittle) and I picked up some random one-way check valve from my mechanic. I have not noticed any performance differences however I did notice that my car has a mini-flutter now surprisingly.. has been like this for several months with no running issues. Will eventually put the Toyota one back in (ordered new from Amayama) but I like the child-ish sound for now