$50 for a cap is horseshyte. The most you ever need is a 3200 or even the 1800 orca is tons. It helps a little with punch as even ultra high end lipos need time to start the reaction to draw current. The cap is instant so punching out of a corner you see an advantage.
If your running a 90c battery you will barely even notice a bigger cap in stock. But in mod it should save your batteries puffing ect.
Honestly aside from the booster business for single cell, you cant get much simpler for electric cars. No balancer needed.
As for being "competitive" its the same in any spec class. How much you want to spend is definitely an equalizer of sorts but driver is always the greatest factor. If you hit stuff, save your money til you dont.