Mis-shifting involves usually when your racing, and your goin to shift into 4th, but u slam it into 2nd, no hell no is it good for the tranny, nor is reving to 9 k in a ls motor.. but reving to around the mid to high 7 range isn't that bad nor is it as bad as it seems, if you do it, i suggest you pull over, check your oil level, your oil pan for any leaks specially around your half shaft and check for white smoke, if you see nor have any other problems your fine, people rev that high all the time, i've had millions of people tell me that My type-r motor can't handle 9300k revs.. it does every, single day..and has been doing it for over 2 months now with no problems, shit i burn less oil now then i did 3 months ago...btw run fully syn oil in that car if u plan on racing it..i've just decided to change my oil every 3-4 months, and ignore the mileage...