18g, this is the problem, change to 16g and it'll spool faster but not by much (1-1.5k rpm difference i think).  18g is meant for 2.0 engines, even 1.8 will suffer huge lags.  and u r boosting 0.4 bars, why? 18g needs high boost in order to function properly, it's hp orientated not response.

trust me, get the 16g and boost at least 0.6 bars, u already have lowered compression and a highly tunable ECU, a higher boost won't blow your engine.  and 0.6 bars isn't really considered high boost, it's just.......standard

and whoever says short runners aren't good for turbo they don't know what they r talking about, i'll tell u, for response, THE SHORTER THE BETTER. Same like the intercooler piping, u don't want cuti-cuti malaysia piping that goes all around the world, it's a waste of metal, if i have a choice, i'll place my intercooler on top of my engine (like subaru did, they can because they use flat engine).....

and your camshaft is purely for high rpm performance, low to mid rpm will suffer like hell, if u want response change to other camshaft, it's no use if your boost kick in at so high rpm but your power band is so narrow