1.9 Lybra; high urban consumption and soot

Hello everyone, I bought a 1.9 jtd lybra a month ago with only 80t km, bj. 1999. the car was checked at the öamtc=adac during the purchase check and everything was in the super green area, also the exhaust values. so on the car really everything is very good, I am very happy, only there are two disturbing things: 1. (the important problem) the city consumption commutes at 9,7l. this is very high for such a motor and I drive very normal. although I used to be a gasoline with 130ps (a rover 620) and I was able to drive just over the 10l under the same conditions. when driving overcautiously with the lybra (I’m talking about absolute annoying slippery with eternally long acceleration to 50 and without climate etc.) I managed at best 6,8l. the lybra rusts quite strongly, when I give full gas, there is an apocalypse behind me and on normal drive with half gas I see already what in the mirror when I look gnau. can be normal n? (the purchase check incl. exhaust check were done yes) 2. (the not so important problem) had a bose sound system and the boxes on the hut rack as well as the woofer do not go. there was a cable under the right floor mat just so there, rolled up. can that be that you still have to connect that, it seems very strange to me? I am very grateful for all answers! dear greetings mat