ES250/2 mit beiwagen haben leistungsbeschraenkung. Normal?

Hello. I just bought and ES250/2 with sidecar in Germany. I see in the KFZ brief that it has reduced power (K 10 and the note m.leistungsbeschraenk.) Is that normal for ES250/2 with sidecar? I'm told by other MZ people in DK that the only thing to change is the "krümmer" to a shorter one since the one used when PS is reduced is 15cm longer and goes in to the exhaust. Can anybody comment on this?. Please answer in German if its easier.