On 93 you should be very close to my numbers or slightly better in some areas. I spent a lot of time balancing the AFR, boost & ignition timing in the areas where I was knock limited trying to make as much power as I could safely. If I had access to 93, I could probably squeeze a bit more power out over COBB's map, but it's honestly really good for essentially being free with the AP. Any honest protuner will tell you this. There's very little power to be gained from a stage 1 "pro" tune. However, there are gains to be had in other areas as it's tailored to your car and your fuel, climate, altitude, etc.
Compared to COBB's OTS, I spent a lot of time in the following areas:
- Leaning out the AFRs at WOT and especially in the cruise areas to improve fuel economy. COBB's maps are conservative and run quite rich.
- Fine tuning the target boost to minimize boost error, integral & proportional gains to prevent boost spikes/overboost as you reach peak boost between 3-4k rpm.
- Smoothing out the ignition curve to improve driveability and reduce knock.
- Changing the throttle mapping. I retained more of a stock-like throttle mapping with the drive modes (I, S, S#) as I wasn't a fan of the single linear response in all of the drive modes. Of course, the drive modes still control the amount of boost that is available.
Carrying power to 7k rpm on ACN91 was quite difficult due to knock and the turbo running out of steam at that point. The VF48 physically couldn't make any more boost up top (with stock hardware), so it was all about balancing timing & AFRs without encountering knock due to the crappy fuel that we have in California.
It was a really great learning experience and quite satisfying. You understand what the "pro" tuners are doing and can go above and beyond since it's your personal car and you have the time and passion. I really can't recommend HPA's courses enough for the price. They really establish a great foundational knowledge. They also have worked examples for tuning the EJ & FA and spend a lot of time on understanding Subaru's knock control system.