TH Sports 125k on the clock.
A little history first. Had all 4 tyres (Turanzas) replaced about 20k ago. Noticed about 1 month ago that the 2 rears were very worn, both fronts still pretty good.
Had the rears replaced, the 2 fronts went to the back and 2 new Pirellis went on the front, 4 balances and all round alignment.
Since then I have been experiencing major vibration when accelerating from about 80kph and up. There seems to be no vibration in the steering wheel or on the road.
But, the whole front end seems to vibrate. If I do the same thing but accelerate very gentle the vibration is still there but is more of a soft tremor.
There is no problems accelerating to about 80kph, and no problems in braking.
I have had it back in to check alignment and balancing. When I bought the Pirellis I was assured that the different type of tyre front and rear would not be a problem.
Any thoughts or suggestions are appreciated.
Cheers

depends what tyres u get whether u can mix and match
generally i would stick to same brand but u can go different quality

i used to have firestone firehawlk's not sure exactly what they were but they were da best tyres gripped like u would not believe. i had better ones on the front originally then when i rotated front to rear i found the front didnt grip quite as well but the rear grip was awesom which ended up being alot better.

Get the wheels balanced "on car" by a decent suspension mechanic. Some alloys are a real prick to balance. Or maybe your shocks are U/S?

Took it to the dealer. They recommended a transmission flush as it could be a sensor that was clogged. Did that $200 no change.
About 4 weeks later on a day that the vibration was happening all the way down to 60kph.
Went back to the dealer head mechanic took it for a drive, thought cv joint or drive shaft.
Booked it in for the testing.
They swapped my right drive shaft for a known working one from another Magna, and the vibration dropped considerably, but there was still some vibration.
Pulled the left drive shaft and put in the shaft from the other Magna, vibration gone.
They put both my shafts into the other Magna, and the vibrations were all there.
Got two replacement drive shafts, balances, wheel alignments and labour costs, all up it was a little over $560.
Here endeth the saga.
Happy driving.

same thing is ahppening to my TL dam it, but mine is still under waranty so hopefully it will be sourghted out by them.

I would also think it could be the torque convertor slipping, as 80kph is around the point at which it engages. If it was wheel/driveshaft balance then it would vibrate at the higher speeds without acceleration.