Go to http://tis.spaghetticoder.org/
Start with the E36 to select your model of Z3.
The manifold is under the engine section.
It looks like a good review of what you would need to do.
2014 435i M-Sport, Mineral Gray, Black Dakota Leather, Driver Assistance Pkg, Premium Pkg, Technology Pkg, 8 Speed Sport AT, Heated Front Seats, Active Cruise Control, BMW Perf Tune, BMW Limited Slip Diff, BBS CH Wheels.
2002 M Roadster, Steel Gray Metailic, Gray Nappa Leather, Black Soft Top, Steel Gray Metailic Hard Top, TC Kline Double Adj Shocks with H&R Springs, Stromung Exhaust, SSR Type C Wheels.