MS Quint Tier 2 vs Tier 3

Intro: MS quint too good but too expensive. Want to save money. Tier 2 not so different from Tier 3. So I should be able to swap a few (if not all) of the MS quints in with the low-tier ones without suffering too much of a disadvantage.

Sources of things: http://leagueoflegends.wikia.com/wiki/Movement_speed

At MS 300 (lowest base MS) 3 Tier 2 quints: 310.53 2 Tier 2 quints: 311.52 1 Tier 2 quint: 312.51 0 Tier 2 quint: 313.5

At MS 350 (lowest base MS + tier 1 boots) 3 Tier 2 quints: 362.285 2 Tier 2 quints: 363.44 1 Tier 2 quint: 364.595 0 Tier 2 quint: 365.57

At MS 430 (lowest base MS + mobility; soft cap applied) 3 Tier 2 quints: 439.0744 2 Tier 2 quints: 440.2096 1 Tier 2 quint: 441.3448 0 Tier 2 quint: 442.48

At MS 500 (for lulz) 3 Tier 2 quints: 488.775 2 Tier 2 quints: 489.6 1 Tier 2 quint: 490.425 0 Tier 2 quint: 491.25

Note: the % bonus from Masteries do not make any meaningful difference in terms of comparing the two runes.

Conclusion If you think 1 MS will make or break your game, buy full tier 3 MS quints. If you don't care diddly squat about a few (1~3) points of MS, you can afford to buy some tier 2 MS quint to save thousands of IP.

...I mean, if having 1 less point of MS was going to get you killed, you would've died anyways. Unit collision would have a lot more detrimental effect on your path of escape/chase than a single point or two of MS.

TL;DR: buy at least 1 Tier 2 MS quint unless you really want to make your rune page look prettier. Dem tier 2 runes so ugly :P