the difference is heat sink and the 358 has 1 plastic gear inside. I noticed between the 2 that my 359 seems a lot more smoother and faster. I have the 358 on throttle and 359 on steering. 359 feels a lot better compared to when i had the 358 on steering. The 358 is an awesome servo as well but just doesnt have that comfortable feel like the 359 has. Kinda hard to explain but its like how some people like the feel of certain radio's this servo to me is like an m8 spektrum difference over an xs3. Just so much faster and smoother and problem free.