been, will likely continue to be due to the massive heat issues and the power it takes to drive them.
Rumor is Audi had two engine mules for the next S4, one twin turbo and one SC. They chose the "safe" route. Can't have 400chp "stock" S4 warranty issues again. The engine is called TFSI which is comical in itself (Turbo StratFuelInj) just like in the 4cyl lines but... its Supercharged for this one. So much for never follow.... hope its better than the C32 AMG in tuning and longevity. That offering didn't last long.
Hal.

Whoops...
I wanna ride...
APR Stg3 (and then some) Sold.