Low boost small turbo setup, is there any horsepower gains worth the extra bucks for it?

12 PSI t3 60 trim

 

YES! I gained 23hp (from 219 to 242) on 9psi with a tiny turbo by removing my cat and adding an external wastegate. Much better overall powerband as well

dyno charts
internal wastagate:



external wastegate and no cat (dotted line. solid line is with an open exhaust cutout):

 

All in all I wouldn't say major numbers. The main thing you "gain" is something you "lose" which is boost creep. A lot of the internal setups take a little longer to spool sometimes because the wastegate will let a some go buy at first. Running an external wastegate and a booste controller is something I alwas recommend. Opinions vary, just what I've learned over time. Good luck

 

Did you have a closed dumptube or open?

 

initial setup was an internal wastegate. currently running open dump

 

x2 what Viper_boy403 said, with another car I had its setup was internal and I would spike 28 but could only hold 23lbs. When I switched to external wastegate with an open dump I spiked 30lbs and held 30lbs (of course with a stronger spring upgrade)