the .48 A/R turbine housing is too small. you need at least a .63 A/R housing. the .48 is causing backpressure... it cannot flow enough exhaust gas out. this is what's causing your sputtering at high rpm and inability to rev all the way to redline without resistance.

next, your regulator is too low. you need at least an 8:1 modifier for the Jackson Racing fuel regulator. 10:1 is preferred.

VTEC is also not conducive to turbocharging. when the VTEC lobes engage, they increase valve lift, giving you a slight pressure drop as more air enters the cylinders. it's only for a split second tho before the pressure equalizes throughout the system. the second problem with VTEC is when the lift increases, so does the valve overlap... that split second when all 4 valves are open to help evacuate exhaust gases in the combustion chamber by using intake air to push it out. in a boosted situation, increased overlap causes "flow through" by allowing boost pressure to escape out the exhaust valves during overlap.

you want to use adjustable cam gears to tune out this overlap, decreasing flowthrough and maintaining power at the VTEC crossover. another avenue is to replace your cams with turbo cams from Crower.