Depends on where you want to go with that one. There's lots and lots of options, just depends on personal preference.
Don't like the look? Want contrasting colors? Paint parts of your interior. Some people paint the vents, ashtray, radio bezel, oh- handles, etc. There's even some how-tos about it. I did it once. Was okay while I had it. Won't do it again.
You could also Get custom floormats with ST embroidered in it, like my SVT mats. Or go to redlinetuning.com and get custom leather boots for your STS and e-brake.
Like billet? Get Alluminum billet knobs for your A/C controls, and "eject" lighter plug/or the "aluminum/billet" one that's 100 times easier to find. There's also matching e-brake handles and shift knobs. You can get them from All over. FordRacing makes some good stuff.
OR... you can pick a secondary color and light it up instead. Put some neons/LEDs/cathodes under the footwells and under the seats (gives your car a soft glow under the seats), or get LEDs from autolumination.com for the dome light to brighten it up inside (colors available). Some people even accent the vents with a small LED inside. Ebay has illuminated doorsills for the focus. You'll have to order from overseas though.
OR... you can take out the stock head unit and put in an aftermarket radio. Which can lead to getting a system put in if you like.. or at least upgrading the current speakers.
There's replacement visors that come with a video screen built in and the wires run invisible through the hinge. Couple that with a DVD player mounted in the car... or even an xbox w/ wireless controllers mounted under the seat. Then your passenger can play games while you drive (I recommend wireless headphones too if you don't want to hear it).
Don't like the clusters? Get an aluminum bezel for it, or change the gauge faces with a new overlay from www.speedhut.com where you can customize what you want in design and color!
There's just to name a few; it really all depends on your tastes.
You could put a dash badge on (I have gotten a lot of compliments about mine... very subtle)...
or get a mirror that auto dims for glare and gives the compass direction and time. Ford makes one for the focus specifically.. but you can find them just about everywhere. There's a company on ebay that makes a wellknown brand used in mercedes... but it's made for our focus.
you guys are forgetting the best stuff!! what about one of those compasses that floats around in some sort of fluid? what about the hula girl with the bobbling grass skirt? what about a beaded seat cover? what about a hot pink hello kitty faux-fur steering wheel cover? what about those dangly little balls that you can trim your windshield with?
no, here is all you need: short throw shifter, dead pedal. anything else is frilly little lacy things and/or extra weight. spend your money on something that actually does something.
shockingly enough, malakai, my expertise in the field of dangly little windshield balls is limited almost exclusively to cheech and chong films. some folks might dismiss them as mere movies, but that stuff is fine art. which makes them films.
more information about interior modification, check out the following: