Motor combo is really dependant on where u plan to drive.
Example, I just finished building a losi 8ight-e, to compete against a mates MBX7eco on a indoor high traction carpet track with banked turns and small jumps.
my mate is running a 2250kv on 4s and it needed the EPA toned down a little so he could hold it flat through the banked turns without having to let off. So considering that I ordered a XERun 150a 1800kv sensored combo for my losi... And it's perfect, it doesn't have the top end but it defiantly has more acceleration and on that track it makes a difference.
There is a lot of debating about batteries. But I'm using 1 of these batteries and my buddy is running 4 of these batteries and has been for close to 12 months... They are only 20c
http://www.hobbyking.com/mobile/view...dproduct=15521
so my recommendation is a xerun 1800kv combo on 4s for track days and 5s or 6s for bashing