Choosing a voltage regulator for Hitec Tx

[colmo]

I have a Hitec Aggressor CRX radio with a pretty rubbish set of NiMhs. I want to upgrade.

I can pick up a set of Vapex Instants for about a tenner, a LiFe 9.9V pack for more than twice as much, or a 3S Lipo for about the same as the Instants.

The catch with the Lipo is voltage - potentially, it would have more voltage on a full charge than the Tx could handle (Futabas definitely can take up to 13V, Hitecs, I can't find anything certain), so I'm checking Maplins for a voltage regulator. I think this is the right one, but am not sure - could someone in the know confirm this please?