Sorry for the delay
Good news and bad news.....
Good news - Car was tuned and felt a million bucks (after 3000rpm). The tune with 1-2 psi less boost
(31psi) and everything else exactly the same picked up 37awhp (about 27awkw gain) gain and held power a little better up top in the rev range.
It proves that going to a sleeved block with a big turbo setup will definately gain you good power increases
Car feels manic once it gets boost (found myself laughing for a long time when I nailed it haha)
Bad news - I've been having this VERY VERY frustrating problem with a low rpm hesitation. Pretty much happens when you give anything more than 20% load through the throttle (more often up a slight hill) it would hesitate and sometimes even misfire @ 2600-2700rpm..
Been trying to fix this problem for th last 8 months or so. It seems to be a VERY common problem in North America for the 07 STI. there is many threads on it but no solution yet (this is different to the 08 low rpm hesitation too).
It was there with the old engine and it came out of the blue.. I just changed an exhaust one day driving home and the entire car just pulled timing and misfired (would not accelerate) I freaked out, turned car off and restart - problem went away strange right..
Next day very small hesitation came and started to get worse over time now misfiring under load and 50% gas. This was on my old engine by the way..
Rebuild my engine as I'm told it was a mechanical problem, new engine and felt beutiful until about 50km's of driving.. Hesitation comes back even stronger at exactly 2600-2700rpm.
Pull AVCS sensors (two blue plugs) and run 0 cam timing (we think it's cam related) problem went away except only when the outside tempreature dropped to 26 degrees at night the hesitation would come back. (soooo friggin weird.. and remember it's singapore 26 degrees is cold here).
Fast forward to today, we have changed, replaced and checked ALMOST EVERYTHING mechanical (compression test, spark plugs, coils, avcs solenoid, put my MAF back on, check cam gears, put a camera in the engine, etc etc...)
There seems to be a new problem now.... Misfire even at idle (cold warm anythign under 3000rpm it misfires)
I believe it is a new problem and not really related.
The only thing that got us a result was when we swapped my ECU with another STI's ECU and ran another tuning software, plugged it in started it up. Problem was still there exactly the same (so my factory ECU is working as it shouild) but the strangest thing.............. plug back my ECU and Car was perfect......... no misfire, no hesitation car drove perfect for 1 day... then everything started creeping back.
thats where I am as of this morning...
I'm told that moving to aftermarket ECU (Hydra or Link etc) will fix the problem.. But I dont want to pay 5k to find out. (I run ECUTEK)