Hmmmm, interesting. My 1200 coupe has NO PROBLEMS with anything above 110 kph. I'm only jealous that your cars will actually GO that fast. Mine won't.

oh ya;
when it's wobling, hold your speed mid-wobble and apply your brake pedal slowly until it changes (better or worse)

my '69 corolla wobbles at 30mph until 35 mph; it's the brake rotors.
one is just slightly warped causing a solid pedal and solid steering, but a higher speed wobble
check your brakes at a really low speed (less than 3mph) and see if you feel and uneven drag

Blofly,You think your vibration is coming from your Air Filter????????

in my cse I can eliminate the engine parts as the cause. This is because at those speeds, even if I shift to neuntral and no accelerate, the car still has the same wobble. hmmmm

maybe it is the extractors hitting on the idler arm? mine does this sometimes while deccelerating while going around a right bend

i have the same problem with my coupe at the same speeds but its comming from the left front and ive tried 3 different sets of wheels and still no solution but it only happens when im slowing down or just cruizing at the 60 - 70 k mark but mine runs twin webers and socked ram tubes so im not sure whats happening
beats me

I have the same vibration at 2600rpm which is between 60-80kmph also I think it is coming from my redline sports air filter assembly

The speedo's not very accurate, but if im not mistaken, the vibration could be felt at about 60km/h to about 80km/h .Once you reach about 90Km/h the vibration starts to die down.

You don't say how fast you are going. We had a guy in the last year, report a similar problem, then told us that it only happens over 90 miles per hour..

A lot of debate stopped shortly after..

But yes, bad tyres will cause a lot of problems.

Even brand new cheap tyres will have problems with balance and vibrations.