Id stay away from off brands. They usually have a lousy spring rate, makes the car super bouncy. I reccommed GC's or Skunks if u want to go with that style. Install is just like springs, except you have to remove some of the brass caps for the install.
Silver, you keep on constantly mentioning some cheap, no name coilovers and people say don't get them. Get a clue, you get what you pay for. If you want those sleeves, then spend $300 and get Ground Control or Skunk2, Skun2 would be my choice since they have a better spring rate.