Hi!I'm from germany and my caprice is the only once in town.because to expensive gas prices and taxes for the car.in germany you must pay every year taxes,how cui your car had and which class of emission.every two years you must check the security of your car,called "TÜV"or"TUEV":brakes,suspension,gaskets,rust.also the emission.so you can't install some special parts(like wheels or thinks like this)without license for the parts and for the car...
BUT:
i did install an 2 flow exhaust system with hedman hedders,2 cat's and stainless steel mufflers by borla,all in 2 1/2 inch.now you really can listen and feel the V8!
i also installed an manifold intake by summit racing.
when i buy the car he got 14 mpg,after install the exhaust and intake 17 mpg.he got ca.25 hp more
maybe for 2009 i plan to buy 19x 8,5 inch wheels on 255/40(why exact these tires?you don't need to calibrate the speedometer!)

i hope somebody unterstand me,my english is not the best.my german would be better ..