... go to a junkyard, find you a T25 turbo off of a TSi or Eclipse. it is small enough to spool up faster and provide more power, or you can buy a new one , or a T28, or T3/T4 from Garrett , they are basically the best turbos for a 4cyl.
1999 Mustang Cobra
Red
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PCM Reprogrammed
STEEDA Billet Steel Flywheel
STEEDA Tri-Ax Shifter
STEEDA Ultra-Lite Rims
STEEDA 30LB Injectors
STEEDA Sport Competition Springs
JBA Shorty Headers
And the beast...
Paxton Novi 1000 Supercharger (only $2500 Holy Sh!t)
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No dyno yet, but definately more then 320 hp.