JimK04....where were you two weeks ago when I was going through this same debate.
Not sure this is the best answer but it has worked great for me....BUT...a big learning curve!
Here is what I used:
Stock 996 3.4 throttle body, 987 intake air box with the back removed so it would fit in my 1998 Boxster. BMW MAF "holder" with a stock 3.4 996 MAF used in the BMW holder. REALLY TIGHT FIT FOR IT ALL. I used a ROW re-flash for my DME because I
did not have smog testing issue in South Carolina. I also removed my secondary air pump and system. Car runs really strong! Had other issues...if you are interested... let me know.
What was the price and source for the X-50 intake you mentioned? I used the stock 996 intake and therefore had to drop the motor and trans to compensate. Also,if you have a "direct cable" throttle it will also cause some issues.
Thanks, Reebuck1