I am a new user on Sugar CE and have 2 basic questions.

1. I am trying to find the easiest way to import customers and prospects from our current system of quickbooks and magento shopping cart. I have been trying import CSV files from each but want to know if Sugar will flag duplicate records?

and

2. If it doesn't or if I already have duplicate records does the merge function work well. For instance, If a sales person has entered a lead and logged a phone call and that person later purchased on our website (Magento) and i have imported that closed - won list can I then go into the contacts and merge these 2 files?

Thank you to anyone with pearls of wisdom.

John