My two cents..
I've got two 808 one on 4s and one on 5s, 4s is great for the track, 5s is too much but is great for the park or smoking Nitro's..
Also.. 4s you want at least 4000mAH if not 4500 -5000, I have the 5s 3700 and get around 20 minutes out of it, its a great $140 lipo..
Either way you cant really go wrong with more power, just learn better throttle control..