I use mine cruizing around town and in the water box at the race track. I actually race the car in drive.
There is derfinately a lag between the time I bump the shifter and the tranny actually shifts. That's why I race in drive. It shifts at 6500 like clockwork. Not so when shifting it manually.
I do really like the shifter around town and on twisty roads, though. It allows me to engine brake into corners and then apply smooth power out of corners without shifting. In the water box when I'm heating the tires before a pass, it's great. I start in first then bump to second, hold the RPM at about 5K and roll out once the smoke gets good. I bump to drive as I approach the starting line.
'07 GT auto, Stage 3 Saleen Series VI blower @9.5lbs boost. LTs, MAC Boom Tubes, 1pc Driveshaft, Eaton posi.
Brenspeed Installed and Brenspeed Tuned
Best 1/4 mile is 11.42 @ 119. Driven Daily