Stock rails are good to 750 rwhp+. Not an issue. Unless I'm mistaken, the stock line (singular, not plural) is good to over 600 rwhp. Also not an issue. The bottleneck here is the fuel pump. I don't expect it to make much over 500. If you were to spend $1000, I'd probably get better tires (and/or wheels), and put the rest towards the fuel system. But I wouldn't do any of that until you got it dynoed and ran it at the track enough to know where the weaknesses are.