Tried to check vvt by taking plug off solenoid on top of engine didnt seem to make any differance to performance even though i later checked across pins 1 and 2 when engine started 12v perminently on.I understand it advances inlet cam timing from 85 to 145 degrees using oil pressure.

Research so far seems to be 2 camps : vvt is mostly for economy and emmissions OR for extra power.
Can someone tell me which it is?

Can someone also tell me how best to check it?