2003 MCS, pretty much all options except NAV. While doing loooong, smokey burnouts in an attempt to finally kill the OE Goodyear runflats I noticed an interesting pattern.

When assisting the looong, smokey burnout with the eBrake (I was really really trying to kill these tires) I would leave 2 nice black stipes. Length determined only by how long I controlled the FWD spin with the eBrake, and if I had the skills to shift through to second and third gears. Which when done properly is really cool and leaves in interesting broken 2 stripe pattern....

When not assisting the looong smokey burnout with the eBrake, (ie, rev to 4k and dump the clutch) I would leave 2 nice black stipes for a short period, then the differential would "swap-out" and I'd continue leaving a single black stipe, always with the left side wheel.

I know that doing burnouts sounds childish, and for all the safety-crats that might read this, I live in a very rural area so not an issue for traffic/children/whatever. Oh, and eBraking the car for an indicated 70mph also leaves long black stripes but man flat spotted Goodyears make a racket. Anyway.....

I posted this in beneath the bonnet as I am interested in understanding this 2 stipe or 1 stripe behavior. These cars don't come with a LSD, and I haven't installed one, so I'm curious why I leave 2 stripes when eBraking and 1 stripe otherwise. I have DCS but obviously switched it off for this excercise (and rarely have it on). I could somewhat feel the car "swap-out in the front going from 2 wheels spinning to 1. Pretty wierd. I cant explain why the differential would not swap-out when I had the eBrake on, but would swp-out when I left it off. "Swapped-Out" is porbably the wrong term, but hopefully you get the idea. 2 wheel drive to 1 wheel drive...

For all of you still driving around on run-flats, get rid of them. I milked my Goodyears for 31k miles and I am soooooo happy that they are gone now. My car is WAY quieter, more compliant, handles better, and even seems to accelerate just slightly stronger.