I'm wondering if the limiter can be deleted on my '08' S6. And if so, what are the pitfalls to doing that.

 

what limiter? speed limiter or rev limiter?

the downfall to the rev limiter is you will grenade the motor if you dont have supporting hardware to allow it to rev higher safely and make power.

the downfall to the speed limiter is if you dont have tires/brakes to handle that you could be seriously injured or injure someone else. it becomes a serious crime if you exceed the speed limit that high if you get caught.