How much spell penetration do i need as a MM hunter for PvP?

I am wondering...thanks for your advice and help in advance.

75 is the magical and balanced number for BGs (practically mandatory) and Open World PvP (kind of mandatory). For Arenas/Duels it will depend on your teammate, if purge is available and wich classes are you facing (mages, druids). Like it was posted in some thread before it affects your shots and traps not only on its damage mitigation but also on the change to resist it; however take in consideration that binary and non binary mechanism (I think, long time that i don't play) are still bugged so you can practicallly say that is not so necesary for Arenas/Duels. The idea of 75 is to mitigate spected Mark of the Wild from Druids when you have a lot of enemies aka BGs.

Thanks for the information.What would be the magical number for 2v2 arenas?I am playing with my disc prist real life friend.

Get yourself the profession jewelcrafting + a secondary wep to use that u can gem 2 43 spell pen gems into. so when facing a team where you need the spell pen you can just swap to it. when not facing a team where you need the spell pen you have some extra resi or agility.

if you cant do that, enchant 35 spell pen on your back and gem 43 spell pen into for example your gloves (to get that 4crit socket bonus) which would result in 78 spell pen. with this you are able to to hit targets with mark of the wild without getting your chimera resisted. this is also good for mage teams that do not have mage armour activated, thus having only 80 nature resistance.

you need 75 spell pen vs druid teams. 120 vs mages. 160 to fully hit a felhunter. hunter pets have 80 nature resistance.

i personaly just have 2 different pvp weps. one enchanted with 2 34 resi gems and one with 2 43 spell pen gems.

Spell pen is rather useless for arena unless you run into trouble with a resto or feral druid