Quoting r4pt0x:
These ports only deliver the oil needed at the piston pin for lubrication. The oil squirters deliver a constant oil stream for piston cooling, which is definitely needed for turbo applications and is even present on most 4G63 & 4G67 N/A DOHCs for a reason. Remove them and you will have massive knock problems, especially when using very low octane fuel as you have to in the US. Piston failure is also very likely as the pistons run much higher temperature, especially if EGR is also disabled.
When doing a proper engine rebuild, the regulator valve bolts and the squirters themselves should be replaced but never removed. I always secured the bolts with some loctite on all engines I've rebuild and never had them come loose, even on engines that generate and/or have to take a lot of vibration (rallye). The few clogged up squirters/valves i've seen were always caused by bad and/or old oil.
I'm running a non turbo block with no squirters at 40psi, no knock issues on e85. The same setup had no issues running 480whp at 25psi on pump gas.