Ecotile tiles can be used with catalytic converters. Tiles might expand through the heat, but they will shrink back to their original size.
Yes. When the car is running the catalytic converter gets extremely hot and if the car is left running whilst sitting on the tiles it may cause the tiles directly under the converter to expand through the heat. This is only a temporary issue and the tiles will shrink back to their original size once the heat source has been removed. In a busy commercial garage it is worth considering gluing the tiles down in-between the lifts or ramps where vehicles may be left with the engine running.