Neu 1515 1.5d, 1y or 2.5d?

This is a tough call for me. I am building a truggy (mugen mbx5t prospect) And am going to race it. It wont be too serious racing just for fun and will be doing some bashing. I am wondering if i should be using a Neu 1515 1.5d, 1y, 2d or a 2.5d bushless motor. I am new into electric and i need power for the tripples on the track, but enough speed to smoke the nitro's (drag racing sort of for fun)
Which motor would would the best with a PolyQuest 4s 6000mah battery?
And where could i find that battery in stock?