There's not really much debate here from me:  I don't really understand tuning.  Luckily, I do understand math - and obviously logic as well.  With that out of the way, we all know the APB engine came with K03 turbos;  assuming the engineers knew what they were doing - the timing curves aren't too bad.  Further along, the ASJ/AZR engine came with K04 turbos.  Again, assuming the engineers had some idea - it'd be nice to start with their timing curves.  (Although, cosworth racing / williams f1 sucks, so can we really take that for granted?  lol jk... no but really they suck.)

Using the WinOLS maps that Tony posted, I was able to extract the four maps of interest:  KFZW, KFZW2, KFZWOP, KFZWOP2.  From this, I took the axis values and timing values.  Having moved all of this into MATLAB, I encountered a few problems.  Of course I'm turning to this forum to help me work through these problems.

Problem 1:  The axis values on the S4 and RS4 maps are different.  I have no problem interpolating, but I was wondering if anyone knows the answer to this question:  Can we change the stored Axis values on the S4 m-box.  Would this cause any problems?  How do we go about doing this?  (nyet please answer, lol)   Is it more advisable to keep the stock axis values?

Problem 2:  The RS4 seems to have a different method of doing Timing Map Changeover than the S4 -  the table KFNW - which specifies the timing map to use - seems to have been replaced by some more complicated scheme;  multiple maps start with the KFNW abbreviation.

Obviously, if we can talk through these issues and figure out the logical thing to do, I'll proceed to implement that in my MATLAB routine and post the most sensible RS4 timing curves I can...

Any new insight into the 2 points from the OP?  I'm most interested in fine tuning the cam switchover, and KFNW insight from the RS4.

Also, with regards to RS4 timing and bigger ports, intake cam difference and compression ratio, for people with 2.8 heads and cams (same size ports and similar intake cam to the RS4), it seems logical that the RS4 timing map might be a good base to start with?  The difference in CR would make it more aggressive with a higher CR on the S4, but most people who are upgrading are looking to go more aggressive timing as well. So that seems like it might fit the bill as a base with the timing maps?