Hi if you are doing 13.5 then both are great my son uses the extreme i have the older v2 but the v2 is 120amp so can handle hot motor if needed.
here is a link to a chat qabout the speedos
http://www.rctech.net/forum/electric...thread-72.html
giantcod sell the extreme in the uk for £60 plus posting not bad tbh comes the next day