Jared's latest setup from the worlds has the spacer in front, but his nats setup had them in the back. Both had the ackerman backwards. I run with the spacer in the rear and the ackerman backwards and my car is amazing. I can cut out 4wds entering our straight from a corner.
If you're having trouble balancing low speed and high speed steering, might I suggest you play with camber and caster blocks. The 4 degree blocks, what I run, will give you more high speed than low speed steering. You can also bleed off steering at low speed and add more at high speed by adding more negative camber in the front. I run -1.5 in the front. Feels good man.