I did a search but was unable to find an answer, so I will ask.

I have an Airtronics M11 FHSS-2 I just bought. Looking for an additional receiver on Airtronic's web site, I notice you can't power it with the 2s lipo in my 1/10th buggy. Do I need to use a recevier pack or is there another way to power this up?

it should be fine, usually the ESC (assuming its an electric) regulates down to around 6 volts to the receiver. i ran a slash with the M11 with a 2s LiPo with no issues because supposedly the power to receiver is around 6-6.6V. i see many electric guys using radios that can not handle high voltage with out issues.