I am buying a new mower this week. I found a 2004 48 Toro WB, 13 HP Kawasaki, for a great price. My question is how are they on hills? I am going to add jungle wheels to it. When I saw the mower today, the back wheels looked really small. Is this normal and does it effect the performance of the mower? Do you think that 13 HP is enough? I have some large properties and I need a new mower, but don't want to buy something that isn't going to do the job. Thanks.