Need suggestions for choosing a good submersible pump

Planning to install a submersible pump for domestic use for 4" bore with 160 feet depth, for a daily usage of 15 to 20 minutes. The bore has been dug more than 15 years ago. Wanted to know a couple of things

  1. What is the suggested depth at which the pump should be immersed from the bottom of the bore?
  2. Is it required to do flush the bore prior to installation of submersible pump?
  3. What is the suggested capacity of motor currently the motor used is 1Hp external jet pump?
  4. Which is a recommended brand that is durable, cost effective and low on maintenance?
  5. What is the maintenance of these submersible motor?
  6. Is warranty a critical factor to be considered while choosing the pump?

Request for a quick response.

Thanks and Regards