I have a xerun justock that I purchased from my lhs. I ran it through a few packs without calibrating it to my radio and noticed top end was lacking a little. I went to calibrate it to the radio(airtronics m8) epa set at 100 and trim set at 0 and once I did the car just shot off like a bottle rocket. It is now stuck in wot with the radio on and will not slow down or speed up with any brake or throttle input. I'm a bit frustrated because I spent $500 at my lhs on electronics, battery, and charger and they weren't able to give me much help with it.

First thing I'd try is to reset everything to default and re-calibrate. Next is go back to the LHS and see if they could pair another radio to it just to rule out the radio .

Would there be any benefit in getting the program card to correct the issue? I was thinking of trying to calibrate it with another radio and just guessing end point settings. When I search the forums there are other instances of this. I don't see why it wouldn't work with a high end radio from ten years ago there's no way i'm dropping $400 on a new radio that only has like two new features.

What Matty said, sounds like you set FT on neutral. Default everything and carefully follow manufacturer process. GL!

seen this a few times.

First have your car turned off

Set your radio EPA at the defaults which I am thinking will be 100 for THrottle EPA and throttle trim at zero. Have brake the same way.

Have the car on a surface so its up in the air, wheels can't touch the ground.
While hotting the set button on the ESC down, turn the esc on and keep holding that set button down till it starts beeping.

Once it does that, you should be able to program it. I don't recall off the top of my head all the steps but it should be in the manual (its something like Neutral, FWD, BRK. Or Neutral, BRK, FWD).

If you find it has trouble setting BRK or FWD, try reversing the throttle channel on your radio and then do setup again.

my thoughts were the channel is reversed for throttle

One idea. Can a m8 receiver handle lipo?

Yeah, I think this is what it was. I swapped the TH and ST cables and the steering servo acted the same way. It seems like the rx got cooked when I put it into calibration mode. I thought the esc were setup to only output 6 volts but I guess standards have changed over the last 6 years?