Originally Posted by hobbesnmina2001

the main disadvantage to using a dyno would be $$ and dynos could cut the time used to tune a vehicle. On the other side of the coin $$ being a factor there is usually more ways to do something and there are good tunes that are developed by doing street tunes. I know of one very good professional tuner that has his own dyno and he told me he still prefers to do street tuning first then puts the car on the dyno to verify and tweek! He told me he prefers that because he can get a better feel for the driveability as he is doing the tune by driving.
On HP Tuners one can do a histogram and log for delivered engine torque and while it does not replace a dyno exactly in numbers it does provide an indication similar to a dyno as to the progress been made.
A professional tuner may not have the time to put into street tune then dyno tune every vehicle depending on his prices, but for a guy tuning and learning in his own vehicle time is not a factor while $$ may be.