There are two things going on here.
He has more G12 pieces then you, giving his ship a faster speed, more health, etc.
So what about the power difference on the ships? You have a level 3 reinforcement, he only has a level 2. That is the reason for the discrepancy in power. That level 3 gives you more "power" but does not boost the ship basic stats.
For those claiming a difference in mod quality, that isn't actually true EXCEPT in the case of going from 5 dot to 6 dot. A level 15 gray 5 dot gives as much boost to the ship as a level 15 gold 5 dot. Nor does the type of mod matter. Health, potency, speed, all irrelevant. Only thing that matters is if it is 5 dot and level 15 (or 6 dot for another boost over 5 dot).