What does it take to make a winning car?

Those Rally Speciales are a quick casting. You should do well with those. 

I'm fairly new to the racing scene as well. But it didn't take long for me to realize that a test track is a must. I tend to want to make cars that are not the normal castings. Ive had a couple decent finishes but no first place yet. Lone when I can send 2 cars. 1as a test for something different to see if it will work and 1 that has been proven to be a competitive casting. I've also had cars that don't stay on the track or go slow or spin on road course tracks. And feel kind of bad when I hold up one of the faster cars and potentially ruin their race because of my slow car.   Trial and error is the game. Figure out what works. Such as quality lube  not the powder graphite for locks and such that you get at Walmart or hardware stores. Also play with the weight distribution. I have recently started using 2 sided tape to place weight for testing. That way I can add or move weights around. Once I find a combination that I think works. Then I permanently secure the weights.  To this point my testing has been on orange track but I've started building a road course as well. On a tight budget so no spoolhead track for me. 
 Gravity Throttle has some build videos and good tips on utube that have helped emensly. 
 So far I've only got a couple cars back from races but tearing them down and inspecting has helped me to get better as well. I watch them race and try to diagnose what I can do to make them better or what may be a potential issue and then try to confirm when I get the car back. 
 One more note. Protect the wheels when you ship!! That package will get thrown,dropped , steps on and be exposed to who knows what kind of abuse. No matter how much work you put into a car it's no good if it gets damaged. 
  ABR (always be racing) I'll watch for you on the track.