Timing can be retarded and allow you to run more boost. I recall the guy who put a supercharger on his NA engine and used TT injectors. I assume he used a TT ECU and I dont know what he did about ignition timing, if anything. But I can make my stock turbos flash to 23-24psi and hold ~20-21 psi, but I have to kick the total timing back to 12 degrees and EGT's go through the roof quickly. Finding the balance between boost and timing and then configuring on the safe side will show what it is really capable of doing. =)