New Audi 80 2.6 V6, a few questions.

Good evening people, I bought an Audi 80 2.6 V6 today for 300€. The car is a 2nd hand vehicle, which had an accident damage at the front right. This was fixed at Audi in Hanover, 2x headlights, lock racks, both fenders, bumper, bonnet, fog headlights Both sides were repaired in the accident and repainted (value: 2214.72€) !!! The car has almost no equipment, only servo, ABS, El. sliding roof and the Wars. 297,000km ran (tooth belt 2012 at 274,000km). All in all a good purchase for 300€? In addition, there are aluminium wheels (no originals) with summer tires. However, I have two questions: The bi-cats are defective, Cheapest possibility to replace them? The front axle cracks extremely when steering, whether left or right. What could be defective here? Love greetings, and photos come from 10.06.2014