welcome to the site

I've only had my ST a matter of weeks, but the vibration you are talking about doesnt sound normal to me. I had an ST170 prior to the Fiesta ST, and actual ride comfort they were about the same. I did a couple of hundred miles to Northamptonshire and back on Friday, and the car was fine - no aches or pains (and i've got a bad back atm!).

If you are getting excessive vibration, as people say get your wheel balance/tracking looked at, and also make sure your tyre pressures are correct (32 fronts, 29 backs).

The only thing I have noticed on the ST on longer journeys is road noise, which is louder than the Focus, however its a smaller car and I expected that.

it can't be as bad as my mk5 on really low profiles when i lost a weight!!

Update...

Well, had my ST for about a month now, done a couple more long distance drives now and got used to the vibrations now. Had the wheels balanced which helped, and getting used to the superb handling, even if the suspension is stiff. The novelty of the folding mirrors hasn't worn off, and I love the 6xCD Bluetooth stereo!
Minor niggles: I keep losing revs when first starting, causing me to stall every now and again in the first 5 minutes of driving when pulling away in first. The trip counter is inaccurate - a regular 220 miles journey wih my other cars suddenly has turned into a 216 mile one. Does the car warp space and time??
Apart from that, a happy owner. Must wash it tomorrow...