You've got to realize that the K03s are still well known to take a dump when only run at stock boost levels which is only about .6 to .7 bar.

The stock RS4 runs more boost than that.

I would venture to bet that every single person here in the US that has switched to K04s will be running higher levels of boost than the stock K03 original figure.

If you want to make things even, talk to someone that has switched to K04s into lowering their boost to stock S4 boost for a year or two and then look at the results....I don't think that you will find anyone willing to do that....because why have they switched if it wasn't to gain higher horsepower...and they are going to be running at least .8 bar or greater. We have raced with K04s for two years and we run consistently with 1.2-1.4 bar and have NEVER had a K04 problem....

Don Istook