It's not a big job at all. Can sometimes take a bit of time, but it's not hard.
Depends how you want to do it (springs or coilovers) and if you want it more for looks or for handling. A popular choice for srpings are Apex -40mm. These give a good look, nice height and decent handling, can be combined with uprated dampers like the apex ones if bought as a full kit, or you could buy adjustable dampers. Eibach springs don't lower as much but give arguably better handling.
The ultimate option is coilovers, you can choose your ride height to suit you, for looks or handling, or both. Can also come with adjustable damping.
All depends on if you want looks or handling, uprated dampers, adjustable dampers and how much your budget is.