996.

The 996 was never marketed as the 996. The dealers called it the 911.

Hey, no ragin on the back seat of a 356. Sure, you can't get laid in one, but I rode from N Florida all the way down to Key West in the back of mine, with luggage for 3 and scuba gear for 2. The trick is to put your feet behind the driver and your butt behind the passenger, that was you can sorta lean against the bulkhead and be comfy. Even fold down the other seat to make a desk of sorts to write on...

The 944. It's the only one you own.

You can also have 9:51 on a digital (or analog) clock. I have a picture of the (working) dash clock in my old 951 displaying that time someplace, so there are a lot of omissions including:

The original "901" (before Peugeot got pissy about Porsche trying to use that # in 1964)
The 917
The 924
928
931 (turbo 924)
952 (RHD 951)

So the clock thing ain't it.

I'm going with 911 because it's the only one that's a prime number.

The 914.

It's the only one never offered as a hard top.

The 916 doesn't count. It was a 916.

POP...

I didn't list them all!!!