Porcelain tile thickness & PEI ratings

[Tommy2000GT]

I found some porcelain floor tiles that are made in Spain at a Chinese tile store for $2.80/sqft. I brought some samples home.

The kitchen floor tile has a #3 on the bottom and the bathroom floor tile has #2 on the bottom which I assume are PEI ratings. Are these PEI ratings too low to be suitable for flooring? Or should I be looking for a PEI of #4?

Also the tiles are a 1/4" thick, are they too thin to be used as floor tiles?

 

[Tommy2000GT]

I just went to another tile store. The irony is it American tile store that sells Chinese tile. However their Chinese tile look to be of higher quality than the Spain tiles at the Chinese tile store.

It's 3/8" thick and PEI rating of 4. But it costs $4.00/sqft.