I work around jet engines every day. Although hot enough for a car directly behind you to be a little bothered, I think the airflow rocking the car would bother them more. I walk behind jets that are taxi'ing all the time. Not real close, but enough. Its not all that bad.
Also, for reverse, its called a thrust reverser. I dunno how well it would work on a car, but on an aircraft its not meant for reverse, just used to slow down.
The main deal is the noise. The noise when reved up would be outragious. The thing is though, at a cruise, you are off the throttle a lot. You give it some gas and pull back to keep you going, just like any other car, so it would only be extremely loud when leaving a stop light or doing those top speed runs.
