Magic Resist Itemization

Currently there are three "big ticket" MR items that give primarily defensive stats: Abyssal Mask , Adaptive Helm , and Spirit Visage . They all have similar price points (2900 g, 2800 g, and 2800 g respectively) and give similar stats: health, MR and CDR (Abyssal also gives mana).

Now, the primary difference, and the main reason to choose one over another, is their unique passives. increases magic damage to nearby enemy champions and has the catalyst Eternity passive; reduces damage taken from repeated hits of the same spell ; and increases healing.

Now here's the discrepancy: Spirit Visage gives 100 more health than the other two items, while they all have the same amount of MR. In fact, and give the exact same stats, for the exact same price, aside from Spirit Visage giving 100 more health, the only other difference being their different unique passives. It's understandable that Abyssal gives less health and the same MR since it also gives mana, and since Spirit Visage has health as part of both of its components it makes sense that it should give more health than the other two items; this logic should also apply to Adaptive helm though. Spirit Visage adds 30 MR and 100% health regen to the stats of its component items ( + ) but Adaptive Helm adds only 5 MR and 50% health regen to the stats of its components ( + + ). Both and give MR, Health, health regen and a unique passive for 2800 g, but Spirit Visage just gives more stats for the money.

Assuming for the sake of argument that both unique passives are of equal value (personally I would say that is worth more since is highly situational) then both items ought to have similar gold value stat wise. Based on a gold value for the additional 100 health and 100% health regen that Spirit Visage adds to its components, worth ~566.67 g, minus the 5 MR and 50% health regen that Adaptive Helm already adds, worth ~390 g, Adaptive Helm needs ~176.67 g more stats; these stats should logically be MR. 177 g worth of MR is 9.83, for the sake of even numbers lets call it 10. Adaptive Helm should give 65 MR to put it on equal footing with Spirit Visage in terms of stat gold efficiency allowing their passives to be evaluated equally in any game situation.

Tl, DR: Add 10 MR to