Stihl MS500i (stock) vs ported Solo 681, Dolmar 7900 and Husqvarna 390xp

The new fuel injected (first ever) MS500i has some impressive stats on paper, 6.8hp/5kw with 79.2cc by only 6.2kg/13.6lbs powerhead weight. A lightweight powerhouse! I wanted to see how the saw keeps up against some older but ported and modified contenders (i know its not that fair). At test against comparable stock saws will also follow.