You using STD ECU bro?Got add-on boost controller?STD boost for skyline is about 350mmHg (0.5bar)
and with minor mod spike to 0.6bar. Boost limit 0.9bar on STD ecu.You will need an add-on boost controller to increase the boost pressure.
His car is far from stock bro..
Ohh then I think 1st step is changing your clutch :), like bro [PIMPIN] said on 100K KM is quite a
wear out clutch if really it`s running on same clutch which ran out from factory. Slipping clutch
make your car lost power and torque in the same time