Thanks for your comments. Good catch dr_broon, going to look into that soon!
So today was header day. Picked it up this afternoon and spent some time installing it. Main problem was i couldn't get my lambda off the old manifold so i had to cut the wires in order to use my ring wrench. Even had to race to the hardware store because my toolbox has wrenches up to 19 but the lambda was a 22.
After some struggling installing it in the driveway i took it for a testdrive. First test there was a leak and now ive got it all fixed up. Only now its really clear the rear part of the exhaust leaks causing an annoying sound. But thats no problem as I'm going to replace the rest of the exhausy anyway sometime soon.
The guy who sold me the header also gave me a pod filter with it. Im going to clean it up and fab a little bit of a cold air intake from another airfilter housing i'll pick up at a junkyard.