CD-audio "Red Book" data does have error correction (Cross-Interleaved Reed-Solomon Code). Whether you get a bit-perfect audio rip depends on how much error correction and retrying you do.
I remember experimenting with writing a CD ripping program in the 90s, using Windows APIs, and I found, like you, that I got different data each time. But modern rippers such as EAC does this stuff much better and will for the most part give you bit-perfect rips.
That mat does nothing. And if you read that linked page, you will see that he claims it drastically improves audio quality (bass, etc.), which is pure nonsense.
I remember experimenting with writing a CD ripping program in the 90s, using Windows APIs, and I found, like you, that I got different data each time. But modern rippers such as EAC does this stuff much better and will for the most part give you bit-perfect rips.
That mat does nothing. And if you read that linked page, you will see that he claims it drastically improves audio quality (bass, etc.), which is pure nonsense.