Your VR4 heavily modded?
Have not use NGK7 before but have tried Denso Iridium IK22 which is about NGK7 heat range. To me not much difference since my VR4 is standard stock engine. Currently using back NGK6 heat range only....
Last week my wastegate fell off at d weld joins of my banana.. Thus went to fix n wrap it up wit thermo wrap altogether.
The turbo was taken out wit all d plumbings disconected.. Everything went fine. But once...