Agree with the 'Stopping power' perk, tried it too and it’s useless on this mod.
About the Car, I did efforts to not be killed and to have the heli but it was down in less than 2 secondes... In another way, I could defrozed easily 4-5 teammates on spawn with the car, without be killed by a nade or bullets, pretty unbalanced. Car is ok but choppers need more life, especially cause it's not so easy to have 9 kills in a row with the hardcore mod.
Snip is difficult yeah, you don't have to miss the first shot. The guy who's far away can kill you with an xtreme facility if he knows where the first bullet comes from. But the difficulty makes sniper's coool eheh :-)