C-Kadett for slalom mountain races and circuit

Hello which cadet do you recommend me for this kind of race? It should be a C-Kadett because of rigid axle and rear drive and of course a Coupe In the ideal case it should be after I’m finished look like this http://youtube.com/watch?v=dS-bpJdHMHs are also available at the coupe also different types udn what should I pay attention to, which has he weakened and which motorization should be in it as a basis (I know depends on the class but what is the best motor)? a car come or you have much. also another one you want to get rid of I also like to take an AUto that was started to build it just shouldn’t be completely finished because I don’t have 5000€ that I can spend for a short time wanting to build the car slowly first then also slalom drive because you don’t need so much motor power thx in advance already