Bottom line ............................ Yes. Many owners of even supercharged S2000s have been running reliably for years without a re-inforced diff. You, the owner, is in full charge of "reliability". You are in control of your maintenance. You are in control of the knowledge it takes to drive the car in such a way so as to better safeguard the parts of your car. "It's not how hard you drive your car. It's how you drive your car hard." If you can comprehend the meaning of this quote, you will have matters well in hand. If not, then get the reinforced diff. You will need the extra "insurance" that it will bring.