Yeah 27turn motors are stock ones for drifting a nice mod 17-19turn is great but your ESC(speed controller) needs to support that low of a turn motor etc
1500mah yes is the hold of the charge thats a small battery prob the one that came with the car trust me get a 3600mah plus and the difference will be unbelievable lol more power and more runtime

Most motors run upto 8.4v(7cell) but i wouldnt go any higher unless running BL(brushless)
Like i said though the tyres are the contact piont and main hopup if you have the standard tyres or the tamiya drift tyres change them out or as a quick fix wrap electrical tape around the tyre and see the difference, the back end will be out lots lmao i use pvc molded wheels from ebay they slide like hell trying to go straight is even harder