Napa filters are on sale until April 30.
Napa Gold oil filters are Wix.
Napa Silver is also made by Wix but slightly lesser quality, but still good.
Napa Platinum is Wix XP, which is an awesome filter like M1, K&N, Bosch D+, but such a filter designed for extended drain is totally unnecessary for 5k.
Through the end of April,
Napa Silver is $2.54
Napa Gold is $4.95
Napa Platinum is $7.54
Other than the Napa Wix filters, I **love** the Purolator PureOne. It is a VERY good filter like Wix/Napa Gold, and many people have even used it for extended drains. But what really makes me go nuts over it is the texture grip. OMG it's friggin AWESOME! The yellow color is cool too.