Sorry to re-open this issue again.
I have a similar thing I have a vibration in the steering wheel and you also hear a humming noise when you cruising in 7th gear around 100-120km/h but I think thats a resonation noise of my milltek race system, in 6th gear it's less noticable.
When I pull hard from 95 tot 130km/h the vibration in the steering wheel increases a lot.
I already reallign the car, roadforce balanced the wheels, swap an entire different rim set, full steering gear replacement, front spring bearings are replaced, also slightly dented my milltek downpipe because it was rubbing against the subframe, but it didn't work, it's slightly improved the vibration though
What can I do next, I'm thinking about wheel bearings or maybe it is still the downpipe that rubs against the subframe...It's really a pain in the ass. I know the subframe is connected to the steering gear but I have that exhaust for more then over a year now and never noticed that kind of vibration in my steering wheel.
Also noticable when you go downhill it's less vibrating, the vibration under heavy load can be felt by 4th, 5th, 6th and 7th gear in 3th gear I don't experience the same because the car accelerates rapidly.
All the help is welcome.
Kind regards
