RE: upgrading servo's
What size RC are you using it on? I bought a Spectrum Radio and it came with two servo's, the two servo's were not strong enough for my 1\8 scale buggy both had about 40-50 oz-in of torque. They work great just not strong enough when the car is on the ground! I think if you run a 1/10 or smaller your servo should be fine! But again its just my opinion! Also if it works, it works, right......my experience was that the lower torque servo did not turn the wheels all the way when on the ground!