Hi Jason, I would take a look at this:
http://www.ebay.co.uk/itm/HOBBYWING-...item3f15fd94c2
This will be perfect on 4s, I use the hobbywing stuff in my Losi 8e and its been great.
I did have a 2200kv motor but this was soooo quick (it would wheely at 3/4 throttle!) A 1700/1800 kv is still super quick (faster than nitro) but you can get good run times on this.
There is loads of info on rctech.net as this is a big class in the US.
The Tekin RX8 is great but fairly expensive so the HW is a good all round choice.
As for batterys the Turnigy 4s hard packs are good and price is very good, check out hobbyking.com for these.
Gensace is another good option too, check out giantshark for these.
Hope this helps, any questions fire away.