ok its a deal..
It will fit series one or two. Came out of a series one though.
You would have to run it up on a dyno to get it right for your std r33
email me : [email protected] for details
It involves all of the above. Deburring to minimise stress points, checking all clearences throughout the engine, calculating final compression ratios , balancing rotating mass etc. All of this and much more is involved