If prepared and tuned properly, you can run some pretty high compression on pump gas. I've personally built/tuned a 2.0 that had measured compression of 12.9:1. It was ran hard for 20k miles with regular service until 2004 when I closed my shop. Can't remember the numbers but it made something like 265hp @ 8300rpm. It was tuned using Hondata, a/f was like 12:1 under WOT. Can't remember the timing numbers, but I wanna say at 0 vac it was somewhere along 12-15 deg.

 

We did a lot of prep work to make it run reliably. We had the piston edges deburred, so as to reduce hot spotting which can be a precursor to detonation. The same was done with the cylinder head. The pcv system was completely reworked so no oil vapor would be present in the intake charge. The fuel injectors were chosen for a wide spray pattern, which isn't so much of a concern with a boosted engine. Spark plugs were dropped to 2 ranges colder than stock. Little stuff like that that you can get away with on a boosted engine become really important building a n/a motor of that magnitude.