I use the ACDelco PF47 in the Alero and PF24 in the Delta.
I use a K&N once and it leaked and for $11 I figured it wasn't worth it to buy again.
I use Nissan filters in the wife's Altima, I don't like them, but they seal really well, ACDelcos for her car are a speical order, but they seal differently than the Nissan ones do. The Nissan ones are almost like a rubberband for the seal

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33% ALEROMOD OWNER!!
2000 Olds Alero 3400 SFI 14.53 @ 94.93
1985 Olds Delta 88 307 SBO 17.96 @ 76.99
2007 Volvo V50 T5 6M 15.782 @ 89.12
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