DON'T USE THE HPI HEX'S!!!!!!!!!!!
100% of the reason guys run 17mm is because 14mm will spin the hex and ruin the rim in very short order. Not as big of a deal when the savage was first made with the 21 in it, but with the 25 on up, you will find that you will fry your hexes out of the wheels very quickly and easily. If you HAVE to go with 14mm, then find an aftermarket hex that has sharper edges to it. The HPI ones were very soft cornered that were very easy to ruin wheels with. Their 17mm hex's aren't any better. I've spun a few HPI 17mm wheels using their hexes with my LRP28.
If you can't find a sharper cornered hex, then I suggest you at least sacrifice the hubs you buy and clean them up really well with DA, lightly rough them up with find sandpaper and do the same with the wheel, then use JB weld to make them a part of the wheel. At least then you get the best chance of being able to run them for a while.