i have a m3 vert with 103k miles i went to the drag strip yesterday and my fastest time was a 14.007 i didnt think that was bad considering i could not take off properly ( the track was slippery)
the time i did do a aggressive launch i spun through first and halfway through second and got a 15.6.
given that the track was as slippery as it was i figured i could get into 13.8-9 range. my car stock was 13.7s at 104mph
if you can keep your car better than stock (new) id say that would be an achievement congrats you did over.4 seconds better i did about .3 seconds worse.