I have an 1999 S4 with K04 and RS4 intercoolers, downpipes, race cats och 3,5" inch rest of the way.
Probably only a REVO stage 1 tune on it.
I have a nasty overboost/boostspike when boost arrives @ 3500rpm when WOT , it goes to 1.5 bar and then it cuts and goes down to 0.7 bar.
I have no boost leaks and the N75 is replaced with oem.
If i goes gently i can manage stable 1.1 bar but drops to 0.9 bar at 6500 rpm.

I can't read the ecu file, probably beacause it has a tune.

So for the questions.

1. Can i flash a stock 8D0907551D.0002 to my ecu even though it can't read the tuned ecu, i know i will loose my stage 1 tune but i'm tired of not be able to WOT.
2. Should i flash it with D or flash it with M?
3. I would love to have some gurgle when i lift throttle, is that safe to try and laborate with and same with launchcontrol?

Regards Johan

You need a tune that suits the hardware modifications on the car, nothing else will run right. Also, you may want to check cracking pressure on the wastegates to be sure they open at the same pressure and neither of the rods get bound. 1.5 bar on stock fueling with ko4s? Yikes. Randomly flashing files to your car will leave you in a worse circumstance, verify hardware (injectors, maf sensor and size housing, etc). Post finding here and we can further help. Posting logs is always a good start.