1. Performance will be increased. The fuel savings come from torque/power arriving earlier which encourages you to up shift earlier. Getting into a higher gear as soon as you can without having to floor the car = fuel saving.
2. Depends on your current mileage. Often a remap is not recommended for an engine with 60k+ miles. This "worry" is because you may not know what kind of life the car has had before you brought it. IF it was mistreated, missed services or had late/incomplete services then problems can arise. However, if you stay on top of servicing you should be okay and you may find yourself servicing more regularly too.
Side note: I had various maps and I mapped at 56k miles. I had major oil burn problems. However, without the map and using 5w40 ester oil my oil burn is minimal. Keep that in mind as you could find yourself topping off the oil more than usual - an apparent Audi design flaw.
Otherwise, I recommend: JBS, APR and Shark. I think someone has recommended Tune it Up or something before. I currently have an APR map - these come with security features as you can put the car into valet mode.