The author has investigated multi-ion modifications to ionized impurity scattering in doped GaAs and their effects on electronic transport parameters. It is found through coupled EMC-MD (ensemble Monte Carlo-molecular dynamics) simulations that a proper treatment of impurity scattering has to include both the many-body contributions and the dynamic nature of the screening process. The simpler single-site, two-body models based on static screening are inadequate and do not yield close agreement with experimental data. The multi-ion descriptions, on the other hand, have been shown to yield the correct mobility values without having to invoke arbitrary fitting parameters. Also, electronic mobility is seen to fall with increasing material compensation as a result of reductions in the free-carrier concentration, which weaken screening and thus strengthens the long-range Coulomb forces. Finally, on the basis of the present results, one can realistically conclude that other parameters of interest, such as the diffusion coefficients and the autocorrelation functions, will decrease and that the noise power spectral density will increase at higher doping and material compensation ratios.