Is there a way to lift the car from the center of the back or the center of the front so that you can change two tires at a time without lifting individual corners of the car? Also, do you have any recommendations as to the best lift to buy or attachment to safely lift the car without damaging anything on the underside?

 

You can most likely do it (we used to do it on a 993TT) ... can't remember where we jacked it from. I think it was quite far back.
Jack ... forget those that supposedly rise quickly until they reach the car. Have yet to see one last. Aluminum racing ones are real pricey, but great quality. There are low jacks (that should fit under your car), but the only one I was able to find has a rdiculously small plate. It's a tough world

 

This is the best jack I have ever owned: AC Jack Very low profile, long reach and beautifully made.