The fins are a good debatable point! If you do a search here (try also "Doel fins") you wll find much heated debate on their pros & cons.....
One thing is certain - they give lift so will get you on the plane much quicker.
Down side if your engine is a long on a short shaft sized transom, those fins will create drag, as will the extra leg length. (Some peeps have posted pics / reports that their fins leave the water once on the plane - that certainly won't happen with excess leg length.) Might be worth trying without them. Worst case - you bolt them back on!
If it's running fine then maybe you don't need to raise it, BUT be aware that you have a lot more underwater, so be careful near beaches / shallow water etc!