Heres what Tim from surgeline had to say about my struggle:
The FP green will support much more power than the 18g. The 18g is a 40 pound per minute turbo and the green a 49. This is just the compressor side of the turbo. There are also notable differences in the hot side of the turbo (turbine) that will make a huge impact on the performance of each.
The 18g is a 300 whp capable turbo that will spool at 3700 to 4000 rpm depending upon supporting modifications and turbine configuration. The green will spool closer to 5000.
In my opinion the green is TOO large for a 2.0 liter application unless you are willing to invest new camshafts and oiling systems to support the higher RPMs need to enjoy such a late spooling turbo. That said, I have tuned many greens on 2.0 liter cars and they do work and they do may power. However, from a drivability perspective I think this turbo is simply too large.
My test for turbo size is all about the driving experience. If I can’t rotate the car around a left or right turn from a stop without dropping or slipping the clutch, the turbo is too large. A green sized turbo will be NO fun on this sized motor.
Feel free to call if you’d have some additional questions.
So looks like i may be steering away from the green for now. That said, which turbine is going to be best mid-high range power, td06h or td05h?
-02 WRX Blouch 18G'd Juggernaut of Beastliness.