Start up question
 

Boxster always fires right up. But, when I get down to 1/8 tank or so it'll turn over a few times before catching. What causes this? Lower fuel pressure? Just curious.

I don't know the answer to your question, but if I might offer some advice, it's really not a good idea to let your tank get that low. The fuel pump is located in the gas tank and, to some degree, relies on the volume of gas for cooling. I've been told that if you never let your tank drop below half then your fuel pump will last much longer. Also, you run the risk of running it dry, which fuel pumps really hate a lot.

I'm probably telling you things you already know, but better to be told something you know than not be told something you don't, eh?

With an electric fuel pump, the fuel pressure should be fairly constant all the way until the tank starts to run dry.

There are a number of other things that can cause hesitation in starting like temperature of the engine, outside air temp, battery voltage, etc, but I can't think of anything that relates directly to the amount of fuel in the tank. Anyone else have any ideas?

Condensation in the tank.
If you can, keep the tank at least half full. Unless I'm on the road, I don't let mine get below 3/4.

Thanks for the input, guys. Not the norm for the tank to get below 1/4, but it has happened.