Exponential might be usefull for adapting better to your ESC/motor combo. Example: Your RC dont move much the first part of trigger movement. You can then use Exp, so the car start moving immediately after you pull the trigger just 1-2 millimeter.
But is that a problem with your current combo? And I would also say, it's an expensive advantage in your case, since you got a nice radipo allready.
Then there's fast response system. I dont have experience myself, so I dont know if it's hype or for real. But it might be worth an upgrade. But they requires digital servos, to be used for their full advantage. AS far as I've read....
Conclusion? Use your good radio and get some nice track experience first. Nothing can beat experience. Even not the most rocket science 1.000$ radio