everything is different. don´t bother, it´d be easier to build a new header yourself. Much easier and cheaper to just buy one.
Besides: Unless you are building a very serrious M30 a header will mostly look good but do very little good. The cast manifolds are pretty good at what they are supposed to do. The stock M30 head will not rev and breathe well enough for headers to be of any benefit. A header will only make sense if you are looking at building a M30 with a very peaky torque curve, basically a track day or race engine. For any kind of street driving you would want a more even torque curve even on a high-Po engine and for that the cast manfolds and exhaust design will work much better.
Even the most potent M30s built by Alpina for street applications stayed with the cast manifolds.
The M30 ain´t no american V8, you know...
