Alright, I thought my service manual would help clear things up, but after a conversation with a friend of mine I'm just as confused. I bought my G20 at the end of February. The woman I bought it from said it was a 93.5. Under the hood would tell you a different story. I have the High port head and AIV, which would lead me to believe it was a 93, not a 93.5. But in my service manual with the 93.5 supplement it says that the VIN's on 93.5 start at JNKCP01D*PT450021, which mine is after. That would lead me to believe I have a 93.5. However, on some other posts I've read that people have 93.5's with High Port and no AIV, and others with low ports. What's the deal? Is there any definitive answer? It's been said before that the 93.5 is pretty much just whatever Nissan had lying around from the old engine in combination with new things. It's not really a super important question, but a confusing quandary nonetheless.