How many rows of data can I Import?

The imports are not restricted by the number of rows, but by the overall size of the CSV file. If you have a smaller number of columns, then you can Import more rows of data.  As a general guide, you should be able to import 30,000 and possibly upto 55,000 rows of data.

Should you require more rows of data than allowed, then simply split your files into multiple CSV files and import separately.