Lady Fingers

I was wondering, I am planning on making Tiramisu this weekend for a date. I noticed a few recipes add whipped egg whites to the marscarpone/egg yolk mixture, while others don't (just marcarpone/egg yolk and sugar). What do you think the difference might be?

Many of the recipes call for a pound of marscarpone, some sugar, about 6 egg yolks... If I did that, do you think I should add like 2 or 3 whipped egg whites?

Thanks