[Devon]

This car would look SO much better without those shopping cart sized wheels. Needs bigger arches and a staggered 18/19 setup with that super high rear end.

 

[Devon]

I totally agree that modifying the rear to lower and widen it would be preferable to going with a bigger wheel but in current incarnation the rear wheel looks disproportionately small compared to the fronts due to that xtra-high butt - needs at least a 17/18 stagger. Not to say it would be practically possible.

 

[Devon]

I would not suggest adding larger diameter wheels on the ST. I have noticed the Fiesta is highly sensitive to weight changes with wheels. Any extra rotational mass needs to be accelerated and stopped. I also think it will be hard to use 18" wheels on the street with the ST. I run 17" wheels with 215/40 17 tires and that is on the edge of what will work for a diameter. Things get a little close on full bump with that diameter.

They'd be expensive for sure but no doubt some forged Utraleggeras are available at 18" with lower profile tires that would result in equivalent wheel/tire weights. Overall height for bump stop purposes would be nearly identical if you went with a 30 profile. Mind you the ride might be a little harsher with less sidewall... I would probably just do the rears with the larger size - not only would it look better staggered but you would not upset the handling tuning as much other than to introduce a bit more oversteer bias with the stiffer rear sidewall.