I had the Hondata for a while, but didnt get to install it and dyno-tuned until recently. I was running on APEXI VAFC2 beforehand.
(Yes I know, the wiring is kind of a mess due to the VAFC2. I will be getting it tidy up soonest.)
I am impress with the S300 due to the amount of parameters that be controlled. through the ECU. Simple stuff like things like Fan operating temp, idling fuel trim with respect to coolant temp, A/C switch off rpm, datalogging etc. (Note to POWERFC Fans: POWERFC may be just as good or better, but I didint get a chance to play with the Tuning Program ;p)
The result after the dyno-tune was 11hp increase in horsepower and 10nm increase in torque, but u will also notice the drop between 5000-6000rpm range, which most likely mean that I have to it road tune too.
At the same time, I did find the engine was running a bit rich beyond 5000rpm at AFR 12.0 (Although it was running at 11.0 - 12.0 with SAFC2 before the tuning), so I decided to lean the fuel over 5000rpm band to AFR 12.5 which resulted in better response and power (butt dyno ;p).
I would like to lean it further to 13.0 but I will only do that when I am able to monitor the exhaust temp.
I must make it clear that the original SAFC2 in my ride was only road tuned and it was doing well in terms of power and fuel economy. But I feel that due to the original ECU close-loop functions, any tuning done on the SAFC2 will not be accurate in the long run. (however, a simple reset of the ECU once in a while will overcome this issue I guess)