Any vehicle can be made just as fast or faster than a VR4 and as far as reliability go its mostly dependent on how well you maintain your vehicle, frequent fluid changes, keeping up on service intervals so on and so forth, but the VR4 is a fantastic car with technology well surpassing that of other cars of its time. Personally id recommend the VR4 over the 300ZX (because i like Mitsubishi better lol) but its your decision, both are great and fantastic cars. whatever you choose enjoy it to the fullest and do your research.
"I know what's wrong, and if I could find it, I'd fix it"
"If a part can be installed incorrectly, it will be"-Murphys Law
"When the valves float you know its time to shift"
"God invented turbo lag to give V8's a chance."