....I had a wastegate problem with my original K03 and had to replace it, which I did with another newer K03 and not a K04.
I'm not suggesting that the K04 is more or any less reliable but that the more you push/modify the performance engine of any car it potentially increases the risk of unreliability and that my personal advice would be to better spend the money on traction/handling mods such as QD also advocates.
Sorry if my post wasn't clear.
Perfectly clear Robin
I know about your K03 wastegate problem, as I am experiencing the same problem (also diagnosed by JKM) and I spent quite some time reading your posts on the matter. I do not believe that it is an isolated incident, as I have spoken to a couple of other gti owners that have experienced similar issues. A few went down the K04 route as a direct result, rather than swapping the K03.
I also totally agree with the traction & handling mods comments.
My question is a genuine one for the forum - what puts more stress on the engine & components; a highly tuned K03 or an AXX/BWA converted K04 (at say, a Stage 3 level of tune)?
Which would people say is more reliable?