[dimitri]

Since you are doing performance DC conversion I would recommend Soliton1 controller. Its almost local to you, made in Tampa, just 600 miles away or so

You will not regret the power from Soliton1, trust me. Try to go with max battery pack you can fit and afford, largest cells ( for max acceleration current ) and max voltage ( speed ).

Sadly, you can't do a performance conversion on 7K budget, it will be more like 20K.