Hi You will need a set of spring compressors and patience. It is not too dificult of a job if you are good with tools. I changed my suspension on 02 A4. Allow 1 - 2 hours per corner.
SHouldnt be difficult... make sure you have an allen key for the top of the strut and a coil spring compressor.... Once its done, get the car to a specialist to get the geometry setup properly!