Can anyone recommend a moderate upgrade to the stock servos on my Tornado s30? I want enough torque to turn stadium truck size dirt tires "2.2", but not so much that I can't keep batteries in it. Right now I run 2500 mah batteries which give me about a weeks worth of run time before I have to recharge. Also this is for rec use so I'm not looking for the most expensive race ready servo either, just a decent metal geared higher torque servo. Thanks.