Greater spell pen. vs maximize

[Sanguine_J3S3]

I'm currently building a fvs which is pretty much close to impaqt's evoker fvs build. I made one difference; instead of quicken i took spell penetration, and now thinking about taking greater spell penetration instead of maximize. My question is; will +5 spell penetration(3enhancement, 2 spell pen) be enough for end game monsters or should i take greater spell pen for +7 spell penetration to effectively land implosion and destruction spells? Basically which monster has highest sr and what is that sr value?

[Crazyfruit]

There are monsters with 21 spell pen I never land on even rolling a 20. Not a lot of them, but some.

Most of the end content that has high spell resistance is also immune to those spells, or have super high saves.

(This is based on elite - if you play on just casual/normal it might be a different story)

[Mellkor]

If by end game you mean epics, then dont bother with spell pene, your insta death spells wont work at all.