You will need a new charger for lipo's.
You can use a lipo and add a lvc with a brushed setup as long as the ESC can handle the lipo. Voltage is fine, as a user posted above it is the amps.
If it was me...
Go ahead and get new charger and maybe a 20c 2s lipo. Then just hook up your new lipo and see how it does.
If it can't handle the ESC you are gonna need a new one anyway
If it seems fine then you are good to go with the only worry is not to let the lipo run low. You can add the lvc at anytime.
Me, I only race at the track. I never run more than a 10 minute race. I know that my 6000mh lipo is plenty, I just charge after my heat. If you are gonna bash with it get the lvc. To get full advantage from the lipo's you will want to go brushless. More power, less maintenance, more power efficient, all that.
Your rc10 is capable of running with the newer 1/10 trucks. I was in a state race when my GT2 died on me. I switched to my $60.00 used RC10gt(which I had just bought the previous weekend.) I finished the Amain in 3rd(the engine flamed out about 10 times, I even had to come down off the stand and start it myself.) Took home a trophy
One other thought.... In my area 1/10 stadium truck seems to be fading both gas and electric. If you are gonna race make sure you will have others to race with in this class before you start dropping money. You will be spending some cash, so come up with your budget and then just prioritize your needs