If you're really into modifying the '04 is a better choice anyhow. There's a lot more aftermarket and the lower compression motor is better for forced induction. I believe on the GTO boards (it's been a couple months since I've looked) all the top 1/4-mile holders are 2004 LS1 owners simply because there's more power-adder options available (having the car longer probably helps matters too).
