HV vs 9L

Hello all

I am sorry if this has been answered before, but I am new here and have not yet found the answer. I was wondering how much faster the 9L/9920 would be over the HV in an E-Maxx. Exactly how fast do they run. I know things can big time depend on how I have my truck set up. I am looking for generalities. Also if ya'll think there is some thing better let me know. I plan on running mostly 12 cells with the occasional 14 and do not want to spend more than 300. This includes getting a heatsink.