General readline on an 1.8t is around 6500-7200 somewhere in there depending on chip, but the engine dosen't produce power all the way to the redline. The peak Hp on the stock engine is around 5300 rpms(the K04 makes the peak a little higher i think its like 58ish). Once you past peak hp you arn't accelerating as fast as you could be in the next gear(generally). So when the K04 tappers at 5000 its about perfect cause its about time to shift but you could take the car up another 1500 rpms if you wanted. So if the e-05 dosn't tapper till later(I read on another forum that it holds strong until 7200 rpms) you can run all the way to redline while still running under maximum axceleration

 

o ya i thought you meant that the 1.8 motor is no good about 5000. becuase i would take mine all teh way to 7500 and it would still be pulling.