I know you've been around here long enough to know that you'd be pushing beyond the reliable limits of the stock block with that much power. Obviously it can be done, and I've even seen guys go seasons without blowing up. My impression of nitrous is that it's even harder on motors because of the amount of low end torque produced. I do not recall if you're already running an aftermarket block, but I presume not, because the overwhelming majority of guys with one are running more displacement. So, I guess I'd recommend sticking with the 150 shot or less.
Also, have you already purchased the rear gear? I'm currently in gear/tire mode with my car, and your 3.73s, I think, are going to need some taller tires to keep your 1/4 mile traps in the right area. I trapped 118mph with a 420rwhp more-than-full-weight hatchback. At 500rwhp, you're likely to go high 120s. I think with the stock block, keeping your RPM below 6000 is smart, and 6k RPM is only 122 mph with 275/40/17s (25.7" diameter). A 28" tire would put you through the traps at 128 at 5700, and you wouldn't be at 6000 until 134.
Also, have you already purchased the rear gear? I'm currently in gear/tire mode with my car, and your 3.73s, I think, are going to need some taller tires to keep your 1/4 mile traps in the right area. I trapped 118mph with a 420rwhp more-than-full-weight hatchback. At 500rwhp, you're likely to go high 120s. I think with the stock block, keeping your RPM below 6000 is smart, and 6k RPM is only 122 mph with 275/40/17s (25.7" diameter). A 28" tire would put you through the traps at 128 at 5700, and you wouldn't be at 6000 until 134.