I've got 60,000+ users I need to import into Kentico with roles and a custom table linking a user to another account (3rd party software). I'm able to import everything I need using the Import Toolkit although it takes upwards of 3-4 ours just to import the users. I've even went as far as turning off versoning, content staging (and logging), commented out any code that migt be executed in our global handlers and it still takes 3-4 hours. Importing the custom table records (same 60,000+ records and does an inner join during the insert) takes about 1.5 hours. Then the roles for the 60,000+ records (1 role per user) takes about 30 minutes.

My question is what are the implications of performing a insert into the Users table without using the Toolkit, API or UI? I really need to speed up the import process and would like to run in under an hour if possible.