Sorry, missed this post earlier. The sky is the limit with servos but the SF-1 isn't really that bad, I would focus on a better steering servo. The hitec 625, 645 or 5625 are good options and Savox has a ton of great servos over all price ranges. Anything metal gear. Some guys I know do well with trackstar servos but I don't know what number they run. The SG shaft extender is a simple bolt on and it looks like a normal crank after that. I don't know where to get the adapter but they are common.