You can also try the Hitec HS-5056MG. I find that this fits the servo mounts and steering assembly better than the Hitec HS-5065MG. It is a closer match to the casing of the stock servo. The HS-5065MG is stronger in torque by 0.8kg-cm. However the HS-5056MG is quicker by 0.01sec. I would love to use my HS-5065MG but it just does not fit my current setup. Either of these are miles better than the stock servo.

HS-5056MG
Speed:
0.12sec/60 degrees @ 4.8v
0.10sec/60 degrees @ 6.0v
Torque:
1.2kg-cm @ 4.8v
1.4kg-cm @ 6.0v
Size: 22.6 x 11.6 x 24mm

HS-5065MG
Speed:
0.14sec/60 degrees @ 4.8v
0.11sec/60 degrees @ 6.0v
Torque:
1.8kg-cm @ 4.8v
2.2kg-cm @ 6.0v
Size: 23.6 x 11.6 x 24mm