Brushless motor and controller for under 700$

[JOHNNYMAXXIMA]

Yes, LiPos will definately help you with the performance aspect. But if you don't want to make that investment, maybe somebody else will respond with the setup of choice for you to acheive your desired top speed because I am not the expert.
One thing I will tell you though is that the difference between my one Maxx that does 38mph and my dual BL Maxx that does about 50mph is the ability to control it. That 12mph difference is huge as far as controlability goes. Not to mention because of the power difference there was the rear diff that I blew, the 4 CVD's that I have broke and the tranny gears and input shaft that went south as well.
All stuff to consider, especially if you don't have the time now to wrench on it. Because that is all stuff that WILL go out on you quickly if you have that much power.