Better rethink that Isaac. The spring can not put any more pressure or weight than the full weight of the front of the car.
If the wheels are on the ground then the weight is reduced by the weight carried by the wheels.
But in the case of a slot car we want as much weight as we can get on the guide.
A spring will not effect the suspension in a negative way. In fact the suspension will only move when the car hits a bump or as the chassis rolls or if your spring compresses like in a banked turn etc.
I believe a light spring allowing the wheels to just float (lightly touching) on the track surface would be how I would set this front end up.