Just to add my comment....:

1 The performance of a lightweight crew with smaller sailplan will differ also from normal crew-weight with normal sailplan.
2 Heavier crew trapping in heavy weather with the kite up will have more momentum and have a better boatspeed when hitting the waves.
3 skills are the most important thing. Not a newer set of sails or weight (as long as your not olympic -> if that will be possible in the future...).

Regards,
Gill