They are going to HAVE to go FI if they are going to keep up with the other high performance sedans.
In particular the new CTS-V ...
http://www.leftlanenews.com/next-cad...orsepower.html
I had an aftermarket supercharged CTS-V and I must say I was impressed with the cars overall performance. In 2008 with its new and improved interior quality/design, slightly more appeasing outward appearance, and the 100,000 warranty - the new 600HP CTS-V should give the M5 a great challenge.