To get this you need to beat Rhymer in his one on one. First you need to unlock his races by getting 50 lights. Second you need to meet his career demands, complete 5 fan demands, complete 2 fan runs, complete 4 fan targets, win event 5 with 1 'X5' fan combo. Fan demands are in the race you will see different yellow symbols on the track which will require you to do different objectives in a certain amount of time to get fans, complete 5. Fan runs show up the same way you need to go through all the yellow gates to complete them, complete 2. To get fan targets you need to get more fans than the target, to get fans complete fan demands and fan runs, hit cars with power ups and finish in first. To get an X5 combo the easiest way is get 6 bolts (to be safe get 9) go behind a car and fire all of them into it, you will get at least a 5 combo if 5 of them hit.
To beat Rhymer you either need to wreck him or beat him to the finish, he is not hard to beat on easy, just remember to bolt and shunt him to get past, and shield against shunts and shocks until you win. To wreck him turn on the mod that gives you 4 bolts each, collect 3 bolt power ups and go behind him, fire all 12 into him and he will wreck.