I ordered and installed the ThunderStruck 10.5 system in my Morgann 33 O/I and could not be more pleased. I went this route because I knew I was going to have to do it myself. What little trouble I did have, the staff at ThunderStruck were there to help with my questions. As others have stated, sorting out prop size and reduction have almost everything to do with performance. It took me a couple of tries but I am now as happy as a clam living on my boat as it doesn't smell like a bus with a fuel leak. It takes me 5min to get underway, 10min tie off when I return. For the do-it-yourselfer, ThunderStruck's system gets a 10 from me!