I'm iterested in a rehab project in which the owner is going to convey the title by special warranty deed. What concerns should I have?

I think my first concern would be a good title search and due diligence, to make sure there are no surprises on there.

Special warranty deed means they will only defend the title for the time that they owned it however long that is could be 1 week or 1 month,if you would be buying with an fha loan the seller has to own the property for a certain period of time (they have this rule because of fraudulent flipping going on and inflated arv values.)

Make sure any purchase is subject to the seller having a clean and marketable title,appraising for the purchase price,and a refundable earnest money deposit if those conditions are not met.

Make sure you get a thourough inspection and that the rehab is up to code.

Get you an agent that deals in this area of expertise to guide you in the process,if you are an agent ask one of the veteran agents to walk you through the purchase.