The tuners claim 25 to 30 @ the wheels on a 93 octane tune. These tuners also have dyno's and I can understand how some may be over enthusiastic with a sales pitch.
I have had a 93 tune and really like the results but do not have a dyno. Not that I would want to check it and complain if they are not up to the claims but would like to hear this discussed here.
Perhaps there are those here whom have did the before and after thing on a Dyno?

 

Not saying its not possible, I think you gain some horsepower on a stock engine, but more important you probably gain a lot of lowend torque and ET in the 1/4 mile also due to the shift points being changed. Maybe faster shifts too because of deleting some TM.
25-30 hp does sound like a lot. Possible, but I think it depends on engine and mods.

 

Not just higher peak numbers, but more average hp/tq across the board

 

yes 25 to 30 is available with a custom tune.