Ok im not going to go in depth with all the info you've requested but i will do my best. A 300ZX has a 3L V6 with around 222hp. You can also get a Turbo which comes with 300hp. The GSR comes with an I4 with 170hp. The GSR might and thats a definite "might" get out quicker but the 300ZX with catch up pretty quick. I own a 3000GT and raced a GST which has 220hp with mods. Now my car has 220hp. Now you would assume that the GST would have smoked the crap out of me. Guess what, The GST can only go 35mph on first while i can go up to 47mph on first. I have more power in each gear which gives me a greater advantage. A 300ZX will definitely beat a GSR without either having mods.