Performance Car Hire. Rent a Porsche from a high performance car hire rental company.
There are plenty of auto rental companies offering Porsche Auto rental or car hire, many of them will be able to hire Porsche 911. It's a great way of trying a Porsche without buying it. There are Performance Car hire companies offering Porsche 911 of all ages, you can hire everything from classic Porsche 911 Carrera, through to modern Porsche 911, 996, 997, Cayman, Cayenne and Boxster.
Porsche 911 make excellent choices for Performance Auto rental companies. A Porsche is easy to drive for car rental customers, exciting yet still durable. I am not sure I would want to own an ex rent Porsche.....but they will fare better than most supercars for hire. You should be able to hire a convertible Porsche, or rent a classic Porsche.
Some companies will be offering Porsche track driving experience, take it from me, it's an excellent way of enjoying a performance car without the worry of damaging your investment. You can search here for Performance hire cars Companies and select a company that can guarantee you will be in a Porsche and not a substitute.
Porsche Cayenne rental, or Boxster hire can often be found with 'main line' auto rental companies rather than the performance car hire specialists.
Bare in mind, that if you are going to use the car on a track, your insurance form the auto rental company may be invalidated, even on circuits such as the Nurburgring in Germany.
If its race track car hire you need then there are specialists for this, usually located near or at the track. If you call the race track that you would like to drive they can often point you at a suitable track car rental company.
Have fun and be safe.