I am looking to upgrade my sons Volcano EPX brushed version to brushless. (he's getting tires of my pede VXL running circles around his truck )

Trying to get 50% more speed.
Looking to use stock gearing.
Looking at these combos:

http://www.ebay.com/itm/SkyRC-Leopar...item46302af083
http://www.ebay.com/itm/Traxxas-VXL-...item5aff0c225c
http://www.ebay.com/itm/Hobbywing-Co...item19ecd41c02

Looking for an easy change out.
Would either of these combos work ?
Should I go higher or lower kv ?
Very confused about kv vs.T.

Any help is appreciated.
TIA.

im using similar to the last link but higher kv and massive battery

Thanks for the info.