not sure if I like him adding weight, might slow him down some. Speed is his game. Will it make him more durable? who knows
If the 8 lbs he gained was muscle and it's all above the waist it shouldn't make a meaningful difference on his speed.
If he had added muscle to his core and lower body, I'd say he could even be faster. If he just added weight to his upper body, he's got the same horsepower as before in his core and legs but now has a higher curb weight. True, 8 pounds isn't much, but it's the fact that he tinkered with it that worries me. Nutrition and exercise can have a big impact on peformance as well as just weight. But my real question is how does 8#'s of muscle added to the upper body make him more durable in his lower body?
Upper body could mean core to some people but it usually means chest/shoulders/arms. Great, Felix will now have a devastating stiff arm in case he's lost quickness.
Again, 8 pounds really isn't much, but if it's upper body muscle/weight, it's at best a non-factor in both the speed and durability columns. Had he added 8 pounds in his core and lower body, I'd say we might have the makings of a bell cow. It almost sounds like Felix wants a modeling gig or wants the next jock spot on Dancing With The Stars.