Cartest is available to purchase as a software program. I believe you just download it. Many have used the program to amazing accuracy determining power made from modifications. The program do about anything you could imagine for a car and performance. It can calculate shift points, determine best gear ratios, best tire height, 60', 1/4 mile, mile, how much power can be made from porting an intake manifold, etc. It's not a "balls on" tuning device, but it's damn close.
Dave
black 96 Maxima SE
Best ET/MPH:
14.31@99.3mph with a 2.18 60'
JDM intake manifold, ECU, intake, y-pipe, muffler