I wanted to report that I had severe stumbles in the 2000 to 2500 rpm range. I changed the fuel pressure regulator to the 2007 STI setup, and this cured my problem. It is so much smoother, more power all over. I would say it is 90% cured. I will now have a final tune by Dave of cryotune, and let you know the results after that. I wish I had done this change years ago. My car is a 2005 LGT 5spd Wagon, with stock turbo, custom tune, up pipe, downpipe, intake and rebuilt engine with forged pistons. Thanks so much to the people that figured this fuel pressure issue out, and posted it here.