Couple of advice questions on the Mini 8ight

[Oh How Original]

Just wondering firstly, how do you guys cure the steering slop in your Mini 8ights? I've noticed their is a lot of play, it seems to be coming from the steering link, so I'm thinking of going carbon, will it improve it though?
Also upgrading my steering servo as this just doesn't hold the wheels at all under power, been looking at the Hitec 225MG, just wondering is their any other options though in the same kind of price range?
And lastly, how do I get more power to go to the rear? I know the diffs aren't sealed so thicker oil in the front isn't an option, was wondering ia nyone here has any tips or tricks to doing it? I get really bad understeer.
Any advice on the above 3 things would be appreciated