x-speed motors canot be run , they did try them at one point but in a 2wd on that surface the rear end traction gave up
we dont have any problems with the radio's , we run 7 heats with 6 drivers per heat , the "podium" is a bench on one side of the track and racers are normally shoulder to shoulder so long as the aerial is pointed up no problems
as for an ma-010 being faster i beg to differ my awd with a stock-r is slower on the dyno than my xmod (i havent raced it with that motor it was just to see how fast it was )
all in all i fyou have the money and a GOOD rcp track get Z's they will rule , but new commers or young racers an xmod is more than fast enough and on a wood gym will out perform a stock Z