Depends on which Boxster. My '02 Boxster S gets 29mpg on 93 octane on highway and 25 on 93 octane in the city. I have a friend who has a '99 Boxster and it gets about the same but just a little better. It just depends on what you consider fuel efficient.
the boxter
Use Porsche antifreeze. Get it from the dealer or online.
The size of the 2008 Porsche Boxter fuel tank is 17.2 gallons or 65 liters.
In the front trunk
$47,600 USD
Rain
Porsche Boxter S, Fiat Panda, Ferrari F430 and lots of Old Rollers
$750.00
near the fuse box
No, the cams are run via a chain.
15- Gallons US
The timing chain is self adjusting.