It will only make your times faster if the shifts are faster. My friend has some pos Ebay shifter stick on his Factory Hurst in his 2000 Z28, it's so short that it's a nub, it takes way more effort to shift with than something taller.
Stock shifters do suck in these cars though. MGW is supposed to be a bad mofo. Avoid the Hurst Billet Plus, it's a pos, I broke one in half, the UPR is like the Triax but cheaper, I ripped the knob off with all the threads on it.