Hey Fellers,
Just wanted to pass on some info I found after about a week of searching. I ran my efirestorm flux for about a year with a NiMH battery and just got a new charger and lipo battery for Christmas. I remember reading about needing to set up the esc for "low voltage cutoff" but I lost the manual and haven't been able to find any info on here or on HPI's website on how to do it. Most people will tell you to get the Castle Link and do it with that but this is one of the few settings you can do without the Link. I finally found the steps to do it on the hpieurope website. There was an extra instruction book with my car that focused on the esc and that info is included on the manual pdf file on the hpieurope site. (Page 40) For some reason the USA site doesn't include that when you download the manual from their site.
Anyways, if you're a looking for the steps to do it click here and go to page 40!
http://www.hpieurope.com/manuals/pdf/10554.pdf
FYI, I finally ran the car today with a lipo battery and wow!