Ilian...
Toolman called me and told me about your post here and asked me to add to what he has already told you. So here is what I have learned and what I know about these as I run a Stage 3 version on my tuned 12v.
The Garrett GT37R Stage 3 is "advertised" as being able to support 370hp over the stock number. So if you add this with the already at 215 which my truck is at from Dodge then it would seem to make at 585hp,right?. Incorrect oh young student of dieselology as not all is as one seems to be when it comes to the manufacturers claims of power.
My 12v was has a ported head, better valve springs,retainers and keepers,redone P-Pump,custom injectors,Haisley injector lines, and a 150/95 45lb FASS to feed its hunger. I have tons of fuel,plenty of timing to light the charger and when at the end of a dyno pull its still rolling coal. Not having fuel is not a issue,not having the proper charger is. See when my truck wants to make power and with this turbo lit at 1100 rpms,when its time the engine want to make the power the charger is out of map. I have learned that on a mildly fueled truck it may be the real deal and lite later and move the map area out where its needed but on something that has a good amount of fuel and timing(ie-a 12v truck) it will lite to early and be done before you need it. I would imagine a 24v with a fueling box and some mild injectors may be just enough to slow it down and lite it later so you can utilize it in its map range better.
They also have a very bad restriction in their so called "power elbow" which is sued to bolt up a factory 2 bolt down pipe. When that elbow is used it has a 1/4 lip(or wall) that extends beyond the outer walls of the exhaust housing and creates a terrible restriction. That will send egts flying off the chart and before I addressed it I had seen 1700 degrees on the dyno. I took it off and went to a flow bench so we could see what was happening and when the gasses rode along the outer walls they then hit the lip and bounced back into the turbo raising drive pressures and exhaust temps. Before I corrected it I had seen drive pressures that were almost a 2-1 ratio with my boost(meaning that if I had 20 lbs of boost I had 40lbs in the exhaust housing). and as you accelerated they went out of sight. Since all it took was unbolting to change the problem my local shop made a HX40 style exhaust flange to bolt in place of the elbow. We then fabbed a downpipe as a standard HX40 pipe will not work as the Garrett is longer and it throws off the angles bad. Once the new adapter plate was on and the down pipe fabbed I went back to the dyno and no more drive pressure issues were seen. Its now a 1-1 ratio and the highest egts I have seen are around 1500 under a full pull on the dyno.
Now I have had this on for a year now and other than the early problems I have had not one issue with it. The spoolup is insane and will plant you in the seat and its one of the nicest driving chargers I have ridden in or driven. It is very user friendly and has a nice tone to it when you spool it up. I am pleased with the product but not pleased it didn't work out for me,things happen and we try other stuff. One thing I would LOVE to try with the way it spools is to make it the top turbo in a set of twins. Ah yes,thats another dream and down the road as piece at the next rest stop.
I hope I helped you some with what your looking for if you have any questions feel free to ask and I will place a couple of pics in the next posts to show some of what we did to make her go... ... ... Andy
Attention: TDR Forum Junkies 
