Each car suits each driver differently. We all have different driving styles. I may be quick with a kyosho but not so much with a losi, or vice versa.

The thing to remember here is that you can't just add a lightened driveshaft or weight saving parts and expect it to make it a different car (just using those as examples)

Your best bet is to drive everything you can get your hands on. Ask guys at the local track if you can drive their cars for a few laps to see how each car is different in terms of handling. Only then can you make the decision of which car will best suit your driving style