Hi, Welcome to the forums.

Tamiya's website and Tower's are two decent ones for upgrades/parts/compatibility. I like the TD pretty well and have a few favorite versions (other than stock) All involve increasing voltage .

Stock 27 t motors with the MSC or an ESC and 8-10 cells
20 turn motors with 8 cells and an esc
14 turn motors with an ESC and 6-7 cells

35 turn lathe motors with 16 volts and a dtx streak esc
45 turn lathe motors with 20 volts and an evx esc
55 turn lathe motors with 24 volts Ka-6 esc
65 turn lathe motors with 28 volts and a KA-6 esc