An awesome cheap servo for steering is the traxxas 2055 servo. It has alot more torque than the 2018. I put it on my buggy and it works great. Hell for about 10 buck on ebay or less you can get one. The stock spektrum 590 steering servo should be alot better than you stock redcat servo and should be more than enough to turn buggy wheels because I have it on all of my truggies.