just an observation regarding wheel vibes .. although at a different speed :
when i bought the car in feb this year .. it had a set of michelin synchrones fitted
in good condition .. 'bout half worn tread-wise .. although with some cracking
at the edges on the rear set .. where the tread 'n sidewall meet ..
i noticed some minor steering shimmy around 75/80 mph ..
later on .. i changed all the tyres to new pirelli str scorp's ..
wheel alignment checked .. wheels balanced ..
still had the same steering vibe at the same speed ..
felt as if it might clear if i went faster .. but had no inclination to try
after a couple of weeks i checked the wheel nut torques ( as recommended )
all the nuts were still torqued to spec. Except for the locking nuts ..
those only needed a very small adjustment ( 16th or 32nd or less of a turn )
to bring them to the specified torque ..
however .. after that .. steering shimmy went away all together ..
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noticed that recently as i had reason to get past a slower moving bunched-up mix of vehicles ..
and wanted to do so quickly .. .. i normaly prefer 65/70 as an 'M' way cruising speed