A:AnswerThis fan is cheap and does not cool well. I ended up buying 1 120mm Antec fan from Wal-Mart for $7.99. It cooled better than two of the Insignia fans.
A:AnswerAs long as the old fan is 120 mm in size, then yes it'll work fine. Don't be confused by the 4-pin plug - it'll fit on the 3-pin motherboard header as the molded "guide ridge" forces proper orientation on 3-pin motherboard fan headers.
A:AnswerGrey = positive and Black = negative. Just try using one set of wires at a time and when it spins your good if you don't hook up to the power supply on the first try it should be fine, it was in my case as I hooked up a 12VDC 900mA cell phone charger to the wrong set of wires and then to the correct ones after it didn't work and it's been running perfectly for months now.