The mod is definately worth it. It is the best hp/$ amount if you can find it used. I have been running with this setup for a little over a year now and have the manifold with AA tune. See my dyno results for comparisons:
http://www.e90post.com/forums/showthread.php?t=727141
I have a spare manifold that needs some slight repair. Haven't gotten to it yet. I installed everything myself and a friend pho_e92. Andrey also installed it himself.
Sx should be able to do it if you are east end.