This work studies the interaction of the DSMC vibrational relaxation models and reaction models of molecular nitrogen at different Mach num- bers where such processes are important. The V-T transition models as- sessed include the discrete Larson-Borgnakke model and Forced Harmonic Oscillator (FHO). The total collision energy (TCE) and QCT models for the NO formation reaction were considered and the reaction from different N2 vibrational excited states was included in the simulations. It was found the vibrational temperature is higher with the FHO model compared to the LB approach since the FHO model has the higher effective vibrational relaxation rates. Furthermore the use of the QCT rates compared to the usual, TCE model gave a substantially higher NO concentration and smaller shock width.