I have had my veccy SRI 2007 for a month now and have had problems with vibration at motorway speeds (70mph upwards).
Easy fix I thought so took it to a local tyre place and had all 4 wheels balanced, got it out on the motorway and vibration still there, not as bad but still enough to hack you off on a long journey. Reading through various threads I wondered if it might be something else so booked it in to my local VX stealers( The Vx Dealers I bought the car from doesn't have wheel balancing facilities !!!!). The local dealer re balanced 2 wheels and gave the car a visual check and reported no problems. Took the car straight on the motorway, vibration still there and probably worse than when I dropped it off.
Really hacked off now, so back on tinternet to look for possible answers and found a site called www.balancemycar.co.uk They claim to have state of the art machines that will sort any vibration problems (machines are called Hunters). Took it to the local agent listed on their website (Buckley Tyres)and was absolutely gobsmacked. They listened to the problem I described and suggested a full wheel test on their machine. I was obviously doubtful after having the wheels balanced before by so called experts, but deparation was now setting in so thought I would give it a go. No problem with watching what they were doing and asking fitters questions either, they were all really pleased to explain the process at every step. The "Hunter" machine" checks just about everything including tyre pressure, wheel balance, wheel trueness (warped or buckled), tyre trueness (deformed etc)road resistence the list goes on.
Results on my car were:
All wheels in good order with no buckles etc
3 Tyres (Eagle NCTs) distorted beyond the point that balancing would have any effect.
1 tyre had damage to an area that could not be repaired .
4 new tyres fitted (Budget Kenda Kaiser 215/50/R17) £247.60 all in.
Took the car straight on the motorway at "serious motorway speeds", no vibration, car fells planted and reasonably quiet, job sorted.
The guys at Buckley Tyres are total pro's and at no point did they try to push me into dearer tyres or wheel alignment or any other services they offered, they were only interested in sorting the problem to my satisfaction which they have.
Hopefully this website might help others with vibration issues.
Sorry for the long post, but sometimes it's good to recognise a quality service when we get one.
Finally, Is it worth having a go at the dealers for a contribution to this on the basis that if they had wheel balancing facilities I wouldn't have had to cough up the best part of £300 to sort out a Network Q car they sold me a month ago ?