We also recommend you review the following HubSpot features prior to importing:
"Sync record ownership" feature. If enabled, this will automatically update the record owner, and might overwrite the data we have imported from your source CRM
"Automatically Create and Association Companies with Contacts" feature. If enabled, this will automatically create a Company record during the import based on your Contact's email domain. This can create duplicate Company records, as Import2 will import the Company relationship to your Contact as it exists in your source database
HubSpot "Insights" feature. This will update specific fields on your records automatically (read more about that here) from HubSpot's database, based on the Company's domain name. This feature cannot be disabled at this time.