Crystal Exporting to excel vs CSV

We are exporting crystal reports in an excel format. The file size is large (approx 35K, 60000 rows). If we export in CSV format, the file size is much smaller (17K for 60000 rows). This may be expected given the differences in format however we need to get the size of the excel file down to avoid timeouts we are having in an app. We do not want to use CSV because we want headings and formatting.

1) does this size seem excessive for that many rows, approx 40 columns?
2) is there anything we can set or do in excel and/or crystal that would decrease the size but maintain the content and format?

Thanks!