Just replace front and rear on my fiances car to pass smog. Used the Auto Zone rental [$25.00, refunded when you return it] crows foot attachments.

Once the front one is loose you can put an open end wrench on it from underneath like Atrosity says.

If you use ARP Ultra Torque assembly lube on the threads it makes them real easy to install, plus it handles high temperatures and has anti-seize properties. Love mine.