Jeff correct any of this if im terribly wrong because this is off the top of my head.
It's Maeda btw.
Turbo's of choice + Fuel Ideas
300HP+
T04
T3/T04[e]
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JWT ECU/SAFC2/Emanage/ETC.
Walboro 255
450cc and up
Cobra/Z32 MAF
250-270HP
T3/T04[b/e]
Big T3 (60 trim and up) [standard t3 can do it.]
[t28 - see also, AceinHole]
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JWT ECU/SAFC2/Emanage/ETC.
Walboro 255
370cc - 450cc
Cobra/Z32 MAF
or
Hacked MAF(?)
[Walbro 255]
370cc - 450cc
or
RRFPR [NOT RECOMMENDED FOR MORE THAN TEMPORARY DRIVING!]
[Walbro 255]
370cc - 450cc
Up to 250HP
Smaller T3
T28
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JWT ECU/SAFC2/Emanage/ETC.
Walboro 255
370cc and up
or
Hacked MAF(?)
[Walbro 255]
370cc - 450cc
or
RRFPR [Again, not recommended]
[Walbro 255]
370cc - 450cc
Cobra MAF works only with JWT.
Z32 MAF is compatible with most piggybacks.
R32 MAF can also be used and is compatible with most piggybacks.
Cheap Injectors
370cc Injectors come from stock SR20DET's (about 150$ total)
450cc Injectors come from DSM's and require a custom fuel rail (about 200$ total)
480cc Injectors come from S15 SR20DET (about 250$ total)
Cheap Intercoolers
Side-mount SR20DET i/c's will work up to about 200HP
Blue Bird i/c's (slightly bigger) will work up to about 250HP
People have been known to stack sidemount intercoolers to good effect.
It is in my opinion better to shoot for about 250RWHP on the KA and tune for throttle response instead of going for 300+RWHP and having to deal with turbo lag. It's cheaper and more useful if you do anything other then drag racing or racing people on the LA on-ramps.
[I've added stuff in brackets throughout the post, as it was fairly long and I didn't want to quote it. ~Jeff]