gorp is right. Magnets "mask" problems a car might have, such as wobbly front axles, non-round tires/wheels and bad weight distribution. I have even read about people using magnets to equal out performance.
Going magless means you have to really approach the car as if it were a real race car. Weight, its distribution, traction, friction, etc. etc. all play a role.
Driving is also very different as the cars slide and drift a lot more.
A few tips:
The car must be pristine inside. No lint, no excess grease etc.
The axles must be tight but have enough play to move freely. Personally I also don't like a lot of up and down play on the front axle.
The wheel must be true i.e. perfect round and rotate perfectly.
The tires must be sanded (unless they are silicone) and clean.
Track must also be very clean.
You will likely have to add 5-15 grams on various parts of the car.
Do you know what kind of weight you can add in a magless car? 5 to 15 grams of what? Any weight having the size of the original squared magnets? Where to find them?
Thanks in advance.