JNormS4

Ive done a lot of work on a lot of american cars but non on german. All I keep hearing is these cars are a nightmare to repair. I have an 02 S4 with broken motor mounts. Not sure if its one or both just lots of engine movement when I put it in drive which Ive seen before from a broken mount. Are these easy to repair? I want to try and repair them myself and want to know how and how hard or easy it is. Also I get a bad wobble in the front end at 45-60 mph broken sway bar maybe? easy fix? it doesnt vibrate at slow speeds or high speeds which is odd to me. Im hoping I dont have to drop the cradle at all during this. I got a check engine light and sounds like an air leak somewhere between the firewall and the engine I get the feeling like thats whats causing it. Any ideas? I would appreciate it guys. Dont want to pay a Audi mechanic $120 just to diagnose my car only to find out I cant afford to repair it.