An assembly of two structural parts of a wind turbine wherein the structural parts are to be connected in a flange-to-flange connection, the assembly further comprising a wind turbine installation system for guiding two structural parts of a wind turbine during installation, the system comprises a guide system for guiding the engagement of the first structural part to the second structural part, wherein the guide system comprises a guide post coupled to the first structural part; a guide receiver coupled to the second structural part and configured to receive the guide post therein; and a shock absorber arranged to dampen shock loads from the engagement of the guide post with the guide receiver.