upright servo postion
 

Iv seen a couple cars online with the servo mounted at an angel and the servo saver facing down. I know this was used on a few 12th cars back in the day, Is it a big improvment on steering?

It gives less ackerman and thus less agressive steering. It's advantage is in reducing bump steer, as the steering links are parallel when on full lock. I just use the laydown servo though. It's a personal preference thing.

Is there really enough weight on the front for bump steer to take effect?

There is enough to induce bump steer, but not enough to make bump steer a huge issue. Hence why the servo is fine in the laydown position.