I have to agree with most of the others.
Fuel in this country is at least twice the cost of fuel in the USA. Licensing your car in this country is based on curb weight and horsepower. The fees are amazing compared to the cost to do the same in the USA.
In the USA I drive a BMW 540i and my wife drove a 530xiT. We really like these models but here it is different. We went with a BMW still but as already mentioned here the size of parking spaces in Switzerland are very small. Consistently so. So we went with a 330xiT as it is a smaller car than the 5 series. There is a reason that so many people here drive station wagons. The combination of practicality and smaller size is hard to say no to. I know as the T in this country means Touring, aka Station Wagon.
As for fuel economy 17mpg isn't that good. I get about 10L/100km which is the same as 23.5mpg. This is my all around mileage. If I am cruising at the 120 km/h or almost 75mph then I get about 8L/100km or about 29.4mpg. Alternatively, on the Autobahn at speeds over 125mph I still get 11L/100km or 21mpg.
My Car holds 60 liters of gasoline and it costs more than 100 francs to fill it all the way up. So for 16 gallons US you will be paying about about 100 US dollars.
Those who say that you should buy something over here are correct unless you intend to buy exactly what you have there. Also consider that in Switzerland it is almost impossible to drive in any direction for more than a kilometer or around a half of a mile. The difference takes some time to absorb as in the USA, depending on where you live, you can literally drive for miles in a straight line with almost no steering correction. There is a reason why American cars are different than European cars or Japanese cars. I would seriously consider checking out the lay of the land here before you decide to bring you car over, if you can.
One final consideration is that the warrantee you have on your current car if any will most likely not be valid. For example my wife's 530 Wagon was still under warrantee in the USA. I called and checked and after a lot of shuffling between different departments I was informed that after the first year the warrantee was provided by the national group. I.E. the BMWNA warrantee would not transfer to Europe.
If you are still so attached to your car that all of this doesn't dissuade you then good luck. Cars are very expensive in Switzerland and if you can bring it here with little fuss then you will save money.
One other point to consider...
Isn't it possible to bring a car into Switzerland without having to pay import duties if you state that you will be removing it within 12 months? I know that if you have owned it for more than 1 year before bringing it into Switzerland you don't have to pay the import duties. There are just some minor fees and paper work as long as you don't sell it within the year you bring it in to the country. I am relating this all off the top of my head so if I have miss represented anything or made any errors please someone correct them.
BTW, we ended up selling our 530 instead of bringing an expensive to maintain non warranted vehicle into Switzerland. We lost 8000 dollars but didn't have to pay the rest of the auto loan, as well as not having to pay the transportation costs and various fees and other costs of inspections, etc. and have ended up more than even.
Thanks and good luck,
Brian