Well, lets start with the price of the house.
It wasn't a $4 million dollar house. The asking price was $1.9 million. The Obamas made a series of increasingly higher bids until the owners accepted a $1.6 million dollar offer. The Rezkos did not own nor did the purchase the house. The Obamas obtained a mortgage to purchase the home. (Michelle has told the story several times of how they got lucky with Obama's book sales to be able to afford it.)
Mrs. Rezko DID buy the vacant lot next door for $650,000. The owners wanted to sell both properties at the same time. They have gone on record that the transaction didn't impact the sale of the house - that the Obamas simply had the best offer.
Several months later the Obama's purchased 1/6 of the vacant lot from the Rezkos for $109,000 - 1/6 of the original purchase price and FMV. Actually, above FMV at the time.
The Rezkos later sold the remainder of the lot for a small profit.
No quid pro quo has been claimed by anyone. In the extensive investigation of Rezko there were 0 allegations of wrong doing or impropriety on Obama's part.
"Plus, I know for a fact Benson will move the Saints to San Antonio if something were to happen.
Posted by taxman"
There was a lot of talk about that when they played some games there post-Katrina. San Antonio was really wooing Benson.