I was also considering chipping my 535d.
But i couldn't resist to try a much cheaper powerbox and try this first!

Just placed this weekend a 89? powerbox from www.abrieb.de on my 535d.
Ordered via Ebay and it took me 5 min to install!

Performance measerad before and after with chrono:
--------before - after
0-100 6.3 5.3 (starting is second gear is better and gives less spin)
0-160 13.5 12.0
0-200 21.5 18.2
0-250 43 34

Really amazing power increase. I don't know how much but my time to f.e. 0-200 is even slightly faster then the video's from Wetterauer chip (40-200 : 17.5s)
Car is pushing so hard that i am afraid to break something.

I don't think i need to go for a more expensive ECU chiptuning now.

Is anyone aware of any engine problem because of a power box?

Can anyone guess how much power i have now?

Take a look here

http://www.bmwland.co.uk/talker/viewtopic.php?t=16932

...fair enough, there probably was ANOTHER problem, but the TB manufacturers do not exactly come out of it without egg on their faces

:thumbsdown: