I had rc6's in my b4, they squeal like an absolute hitch but the performance is unbelievable. I don't know what happened with Dec's set but mine went through 4 track days plus daily driving for over a year and there was still 50% of meat left in them when I sold the car.
To counteract the squealing, I used to spend half an hour every 4-6 weeks applying some fresh copper grease which stopped them from squealing.
They are terrible on your wheels though, they will destroy them unless you religeously clean them and de-ironise them pretty regularly.