Drove down to have my smog today. Barely passed 2 years ago with stock tired 4.0, crappy aftermarket cats and borla cat back. Over 165K on the stock motor and plan on turning over the 90 soon to have the new 4.6 top hat motor dropped in. I figured I would go ahead and refurb the exhaust and smog before the engine work. Ceramic coated factory headers, new Y pipe with CA approved magnaflow cats, 4 new O2 sensors, new borla muffler. Voila!
Not bad for a thirsty V8. With the new motor and tune I should be in prius territory.