Maybe a little clarification. The other poster, Anm6, had great results from the HT until he went "big turbo" with the PG reworked turbo which flows about 30% more than stock. With the bigger turbo, he needed a custom AP tune to get his car running properly. Just too much flow.
With my mods below, I am holding 18-19 psi coming up on boost and tapering to about 17 at 5,500 rpm and still 16 psi on out past 6,000 rpm. The load tables have been raised in the mapping so that you do not hit the 17.5 psi slap down on stock tune. The adjustments to timing advance and boost appear to be based on keeping EGT's close to but not exceeding 1500 degrees F., rather than attempting to dangerously lean out the tune as with some other options.
I am now hitting consistent 60-100 mph times of 5.8-5.9 seconds in cool weather, 6.1 seconds on warm days. Think about that for a minute in comparison to the same time intervals for some cars many would consider to be pretty quick.
I think there is a bit more going on with HT's approach to tune beyond its ability to overcome the sharp 5,500 "fall like a rock" throttle closing of the stock tune, and the lifting of the restriction in 1st and 2nd gear.
It is not capable of absolutely maximizing power. To do so does run risks HT does not wish to do, and which conservative owners of daily driver cars like myself appreciate.
It is quite mod friendly as long as you stay with the stock turbo. It produces a very broad, flat power curve, raising power "under the curve" compared to stock all across the band, not merely up top. In fact, my assessment is that the best power gains from HT, compared to stock take place on the left side of peak power. Whether you are producing a higher peak power number is not nearly as important as getting more power early in the power band and holding that rise throughout the band. The earlier and longer the power rise takes place is more important that peak dyno numbers.
I agree that it is one of the best bangs for the buck for those of us who want more safe power.