i had a friend with an OBX header and when he installed it the O2 sensor bung was too far in and it burned up his O2 sensor.
he ran rich for like 4 months it it robbed him of so much power and mileage.
please dont buy something like that, go for DC sports or Greddy, but only in stainless steel since ceramic chipps off very easily.
o yeah his CEL was on too