hi,

underpowered...not really,the main difference for me was i went from an s2 turbo to the st170 and the power delivery was different,a lot smoother instead of a kick in the back,which i do miss.Should max out at about 135mph maybe a little more.0-60 in 7 ish seconds (standard)

The faults yes there is a few faults main ones being cat heat sheilds,Faulty hego sensors and i personally had a problem with the steering lock armoured sheild which took ford 7 weeks to find me 2 shear bolts to rebolt the original back together after a bolt fell out

The car in its self is brilliant,i used to have t/a koni on my s2 and the ride was great but on the st170 in standard trim its a lot better, its like a go-cart,

The brakes are absolutely superb disk all round,

Petrol consumption should be up around 350ish to the tank about £40 about 36mpg ON A RUN not urban of which i dont bother checking,

Loads of boot space,tyers go at about 20,000 mls
and i must stress if you do buy one get as many optional extras you can afford,if you can see your way to getting full leather it will stand you in good stead,
if you were a bit closer i would let you take mine out,
i have thourght of selling mine recently as i feel the urge of a turbo car again but indecisivness has let the chances go by...
still anything else i can help you with give us a shout