exhaust now, no worry.
super neat thing with your ecm is the ''knock sensor/ electronic spark control'' that retards spark to minimize danger of engine melt-down (albeit at a major reduction in power) ...hafta go much deeper with mods before you outpace this feature.
bumping up the fuel pressure a bit (3-5 psi) after port/polish plenum should get air/fuel mix back to near perfect with the stock programming already in your chip...the ecm relies on fixed memory to feed the engine during the first 2-3 minutes running (cold start) and at W.O.T. (anything more than 3/4 throttle open) and higher pressure=more fuel --same as a modded chip will do by longer injector 'open' programming...during part-throttle (normal driving) the ecm starts with memory baseline and 'learns' (reprograms itself) to get 'perfect' exhaust discharge = perfect air/fuel input by datfrom the o2 sensor (unless you get wild with mods, exceeding the physical capabilities of components) so fuel pressure is not critical there.
the stock chip program is conservative with spark advance to reduce the manufacturers (gm) warranty exposure, live with poor quality fuel, etc...an aftermarket chip that gets closer to the 'ragged edge' will usually increase power a bit, but premium fuel is mandatory
air pump only affects what goes on inside the exhaust pipes during brief periods and has little effect on anything except increased noise of the pump itself, mpg reduction due to component weight and drive belt friction, etc...no danger to engine in any configuration, questionable environmental impact, local vehicle inspection may mandate retention if oe equipped.