The special events are clearly flagged with "your investment in R&D is paying off commander", and they give you 1) either shield recharge or emp shield destruction 2) Stimulants (damage reduction) or supercharge (boost move and attack speed) 3) Recharge (completely refill all charges of everything 1/wave) or Aux Boost (10 damage to all aux cannons, including frost/fire). I agree about the percent chance for improved options, though. I assume it's what determines e.g. 10% v.s. 5% bonii and the same for +30 v.s. +40 credits but I'm not sure.
Napalm is indeed awesome.