TBH, if you spent another 10K on the 370Z, you'd prolly beat them all and still be cheaper than the nearest price rival.
You could replace the suspension with say KW Variant 3, add a full Motordyne exhaust (ART pipes, xyz pipe, true dual shockwave), induction kit and an UpRev tune at Abbey Motorsport for less than 10K really, maybe even squeeze a Vortech in there with that budget.
Just thinking out loud....
EDIT:
prolly forego the Vortech and replace all the bushes with stiffer ones, replace the antirollbars front and rear and if any money remains spend it on laps around The Ring, lol