Well the speedo is 3MPH off at 55-65 so I know how to compensate for that one...(I have my own GPS...go go search and rescue!)
I used my wristwatch with a stopwatch on it to time it...fairly accurate
I was hitting 11.8-12.2 or thereabouts on this road I was doing...averaged out the runs (I ran the road both ways multiple times)
Its extremely peppy now that I adjusted the ALDA...runs 9psi boost currently as well.
The only thing of weight in the car is a bag of sand in the back along with a tool kit.
I started out with about 14.5-15.5 second 0-60's and got it down to, essentially, 12seconds...
Engine was a bit warm after these of course...so that may hinde the speeds a little.
One of the runs I did the defroster was on I forgot to shut it off and was like, "why did I just snag up 2 more seconds?"

Also I weight about 145lbs...6'6" but 145...so not much driver weight.