On the original GTO it came with a Muncie m-20,21, or 22 with a Hurst shifter. Some had a little sticker on the dash saying " This is a genuine Hurst shifter. Shift as hard as you like but don't hurt your arm." Some of the mags have suggested the 04 has a somewhat soft or mushy shifter. Any of you guys with corvette or firebird/camaro M6 experience have thoughts or comments? Can this be upgraded?