Tuning, Timing, and Boost questions

Well, I was doing some research on the tune in my MK7 GTI (Unitronic stage 1+) and from what I can tell, this is a mostly "timing" based tune, where as APR stage 1 tune is boost based peaking 25-26 PSI, where I peak 18-20 PSI.

I understand that boost and timing play a significant role in providing more power. How can a "timing based tune" perform similarly to a "boost based tune"?

I assume, adding timing ie. spark fires later on the compression stroke, adds more power?

With boost based tunes, is the timing changed much?

And yes, I know everything is variable to different tuners / manufactorers, this is for general knowledge and discussion.

When I was playing around with my WRX I saw a lot of tunes (and I'm pretty sure even the factory tune) putting out single digit degrees of advance at high boost and rpm. No idea if there was anything to gain by easing up on the boost and adding timing would help peak power but it would probably be a little more responsive.

If you really want to know what's better you'd probably just have to test it both ways. And test permutations between the two extremes.

I'm guessing the factory tune has pretty safe timing. Based on that the 'timing tune' probably gives it a more aggressive timing curve on stock boost to increase power. Where as the 'boost tune' probably increases boost to match the timing of the safe tune.