Unfortunately, manufacturers put YEARS of research into all aspects of a car to bring them into line with one another and to make the car a cohesive unit. Exhausts are developed by trained technicians and MILLIONS are spent on getting each one just right, switching parts in and out all the way until the perfect combination is achieved. Your average aftermarket brands just can't do this, they'd have to charge so much they wouldn't sell any exhausts. The f-type actually has a switch for the exhaust to change it between loud and manageable. Without splashing out a couple of thousand on something like an invidia, borla or magnaflow, you're going to have to compromise somewhere down the line. You could get a slightly noisy exhaust and quieten it down with removable baffles, not have the exact sound you want or get used to some cabin drone.
Or I suppose you could stump up the extra cash and pay someone to make the f-type exhaust fit the Z? However, that might well be a pointless exercise as there's so many intake/engine/manifold/exhaust variables which could affect it you'd just be chasing a pipe dream. The only real way to get that noise is to buy an F-Type I'm afraid