Beware, I put Magnaflow cats on my Xterra. Had codes or issues but the early 2nd Gen Xterras are known for catastrophic cat failure that is believed to destroy the rear cylinder on the side of the engine the Cat detonates on so I did it preemptively at 160-some-k miles. New O2 sensors and all.
Started throwing a code for PS cat. Email MF and they said "I should have repaired the issue with the engine when you replaced the cat." and refused to warranty it despite telling them repeatedly there was no issue, I changed them to AVOID an issue.
So now I'm out that money and will NEVER buy another.
I'm considering the aFe cats for the LJ since I'm popping warmup codes for both primary cats.