Why would 1/2 offset hurt steering? I run those wheels on both my truggies and hasnt affected the steering at all. Did make the truck more stable and if anything made the steering better.
I would check with your track as to what their rules allow.
Alloy knuckles will take up some of the steering slop.
Stronger servos and better tires and you should be pretty competitive.
Oh and if you have already done so, upgrade to a 2.4ghz radio.
Do you have a link to the charger you ordered?