Porsche Repair: Books manuals etc..., mass air flow meter, mass air flow

Question
I saw it ... I bought it! 1984 944 porsche manual trans. I love the front end shape. Never winter driven, 101,000 km. No rust. I'm an aircraft mechanic...so can twist a wrench (I think...humor)
Q1...Are there any (must be out there)books or manuals which explain well the fuel injection system, emisions, and ECU system. Something that will explain in detail what to look for and what each part does; for instance I think it idles high..1100 rpm warm. Why?..this could be several things. where do I begin?
Q2...I've noticed 2 items on the internet claiming to improve engine performance first  VTX Performance inhaler(kit)... essentially an intake filter... do they work and increase horsepower...keep in mind there is a module "upstream" of the filter I think it is called the mass air flow meter.
2...  Throttle cam made be weiltmeister, I think it simply reduces the foot pedal travel, so the engine revs quicker. Leave it alone?

Answer
Henry,

1.  Go to your local auto parts store and buy the Haynes Repair Manual for the 944.  Don't spend more than $20.  You can probably get the manual less expensively at a used book source on the net, if you check around.  This would be an invaluable aid in getting an excellent introduction to your very cool car!

2.  I'm not familiar with the VTX Performance inhaler, so I can't comment on it.  On the question of air filters, I never would have believed this claim, but there is proof that having a certain K&N filter reults in better airflow than having no filter.  Has something to do with actually reducing incoming air turbulence associated with normal incoming unfiltered air, by lining up the air molecules in neat little rows...so they enter the intakes's airstream more efficiently.  Add this to Ripley's believe it or not...I guess.

3.  Leave it alone for the time being.

Now my turn for questions:

1.  What's the condition of the "timing belts"?  If you don't know EXACTLY when they were replaced last, park the car till you do.  2.  Of all the wonderful design elements and the sexy front end of the 944, how do you imagine the Porsche engineers getting away with putting rubberized belts deep inside the hot and possibly oil contaminated engine??? 3.  And how long do those damn belts actually last?  4.  And what happens if one breaks?     

Have fun with your new baby!

Dave