What is the price difference between a mid-range and premium solar system?

What is the price difference between a mid-range and premium solar system?

Component quality - Premium panels and inverters cost 20% more. The quality of solar panels and inverters can vary. You can find anything from cheap, poor-quality panels and inverters that are best to avoid, to high-end premium panels and inverters with extended warranties. 

Micro-inverter or string inverter - Solar power systems using microinverters come at a premium (typically $2000 more) because micro inverters can maximise the amount of electricity produced at each panel.