HV vs 9920?? Talk me out of the hv maxx

The hv maxx is simple plug and play. Tell me what a need to get a better brushless set up for about the same price?? 9920 and 8l or 9l ?? What else would I need to get my emaxx up and running? it is already all set up with cvd's clutch ect....... I have 8 six cell GP packs for now...... I dont need speeds above 40mph ect..... is this set up compareable to the hv maxx or alot faster if I want to upgrade batterys ect?? I just bash in the back yard and want some more power and speed.... The one reason I dont like the hv maxx is cell limit..