So, should I change my head?

[s13eater]

well tbh, its what ever you or your tuner prefers, unles you are mapping it yourself, i know from what i've been told that the dta software can crash a lot, i had no probs on the omex and it was on the same engine that you have, the ca18et, i ran the t34 and there was no probs with lag, although i had a well ported head by AMT engines and mapped by the same company, it came on boost about 3400rpm, although the sxoc crew say the afm is good for 270bhp, thats on a det engine which breathes better to start with, 54mm is a bit pathetic to say the least, you need at least a 2 3/4 inch exhaust, i used 3 inch, big turbo, better with the external wastegate, anything that makes the engine breath better is a must, the theory that because its forced induced, that you just run more boost and it will force the air through that it will be ok is bull,get the air flowing as good as you can, i've a few tricks on the fj which will help the flow and speed things up, but you will have to do some home work yourselves for that .