The suspension is actually the flexibility of the knex under load but you can put real springs in place of the spacers on the suspension.
Step 1: Front Suspension and Steering
Step 2: Front Frame
Step 3: Driver Tub & Engine
Step 4: Rear Suspension
Step 5: Putting it together
Step 6: Wings
Step 7: Modifications
Excuse the dust, it was in storage.
What I changed was the rear suspension, I moved it closer to the front of the car.
I also change the rear end, and put in a mock transmission.
These pictures are of the car in non-wing 1967 spec, and winged 1968 spec.
I think that the modification really helped with the looks of the car.