the install was not hard at all really, depends on how much wrench time you have done and modding you are comfortable with, I’d peg it at moderate difficulty, basically if you can install coil-over’s on your car you can do this.
The intake manifold requires just a bunch of disconnecting and unbolting the main studs holding it in the head and remembering where they go afterward. All the wiring is their so you don’t need to rewire or splice anything, its truly plug and play.
the car is in storage for winter so I haven’t had it out yet but maybe the next nice day we have I will take it out. I’m here in the Michigan fort Wayne Indiana area so the grey skies are starting to take over.
for spring I plan to do the full dyno and I will post results. and will be working with Active autowerks later in February to make a tuned map just for the Z4 that everyone here can use if they choose to do this mod. The personal requests from the members here on the forum say they really want dyno before and after results so I have chosen to wait and do a stock dyno pull with just the manifold swap and then do a tuned pull to see what we can truly add with the ecu tune. the existing dyno results on an N52 325I motor with a more restrictive exhaust than our Z with over 120,000 miles returned a net gain of 10HP without a tune. there is no tune yet specific for our Z4 with the manifold swap, as the 3 series has different more restrictive exhaust and such. I plan on taking the car down their around February 2011 to have a custom tune done and with a available SI Z4 their so we can compare numbers. this way we can track down exactly what we need to do to get the full HP possible. After this tune others who have a Z4 and want the tune can get it without having to dyno their vehicle.