Has anyone swapped their lower unit from single to duo-props? I wonder how much, if any reall improvment there is and if it is worth the investment. One item I found interesting was the ability for a single to "walk" at slower speeds in its own wash when docking. Also, is there added performane beyond control (with a duo) while on step? One marina I talked to said adding a duo prop would help compensate for repowering with a smaller (6 cyl from 5.7 liter) but I cant seem to find any supporting info online. Hopefully some out there will have some personel experiane to share.