NG horsepower upgrades

[David.Payne at brinksinc.com]

I'm looking for some logical paths to take to up the HP of an NG motor.  I
want to keep the CIS (just spent a bit fixing it all), and want to maintain
as close to a stock appearance under the hood as possible.  Some of the
questions I have are:
Is the 4KQ manifold and downpipe more efficient than what I have (1989
90Q)?
Is the NG head basically the same as an 8V hyd. GTI head plus a cylinder?
Dependent on the answer to the previous ?? what is the recommended valve
sizes (head and stem)?
How much compression can I get away with using 93 octane fuel?
What is the best cat to use?
My current plan is to use Blau's cam, enlarge the TB, fab up a 2.25 inch
cat-back exhaust, mill, port and big valve the head, shoot for about 10.5
or 11 to 1 compression.  Desktop Dyno says that with 10.5 comp, 42mm intake
and 35mm exhaust (I guessed on the sizes) I should have 155 hp at 6000 and
162 lbs/ft at 4000.  Using the same combo on the 2.6 bottom end takes you
to 161 hp and 173 lbs/ft.  As good as the leak down numbers are on my
engine, I'll have a hard time justifying the 2.6 bottom end.
Alan Pritchard, lets compare ideas!
TIA,
Dave Payne