Do you know what your discharge air temps are? Meth / water injection can cool the intake charge by up to 150 degrees and raise the effective octane of the fuel by a few points, which could allow for significantly more boost if you tune for it. However, if you go this route, make sure you have some way of driving the car safely if the meth injection fails or is disabled for any reason. Several companies make kits that can detect faults in the system, but you'd still need to handle the fault condition in some way.
I plan on running meth as extra insurance when my build is finished, but I don't feel comfortable with relying on it to prevent detonation. Rather, I will use it to keep IATs down, and to raise the octane of my fuel for extra knock protection. Your tolerance for risk may be different, however, so don't take what I'm saying as gospel.