err... if u are prefer to run with auto, think u can look for replacement high flow air filter, spark plug and plug cable those basic upgrade to increase ur throttle respone first.
Boost goes up nicely to 0.5 bar at 3000rpm but then starts to drop to 0.3 bar starting 3000rpm until 4500rpm. After that it fluctuates about between 0.4 and 0.3 bar until 6000rpm. Any idea why? Boost leak?