hye guys, i hv 2 questions, i just bought my car for about 1 year now, 2003 wrx sti version 8 jdm...

1)my car make a clunking sound, it gets worse when driving on normal road.. i thought it was caused by my stock suspension, even when i changed to after market coilover it still the same.. anyone have experienced this problem..why n how to solve..

2)i hv hks evc6 installed, after a while(now), when hitting boost 1.0++ bar, it wouldnt go, like my turbo wont functioning, it makes sound like "brrrrrrrr".. now my top speed only 220-230km/h and took a very long time...0-180kmh is ok, but top speed, even old guy driving an old merc can just leave me behind.. so embarrassing.. when to take over a car i hv to change gear, like no torque... why n how to solve..

thanks guys