Yea the rx cap is the cheaper more convenient way to go, it's not guaranteed to work though, I ran a savox with a rx cap on my spektrum rx with a HW sct pro esc and it still had brownouts, I ran the same servo with my mt4 rx and tekin RS esc with no cap and didn't have any brownouts, both esc are at 6.0v, so seems to be certain receivers brown out easier or different escs are weaker to supply the rx the power under a heavy load