Are they even legal?
I would check that out. I know that in Vic that a down light without a protective cover is no longer legal from a electricians point of view. All down lights need to have some sort of cover as they get hot.
My sparky told me that for my electricals to comply, I must install the other down lights that have covers. My partner is a builder and confirmed. Should be referenced in the 2008 BCA.
I would be real care ful if you are buying those down lights as I think that they may not even be legal. Any sparky who wants to continue being licensed, will most likely not install them. Also as you are probably aware, sparky must install them.
Worst case scenario, your house burns down and the insurance company doesn't cover you.
If by chance they are legal, my question is whats wrong with them, coz that is a crazy cheap price.