Quote from That3rdGuy
Then again, physics don't exactly apply, seeing as Luffy gets hot when he goes 2nd gear or uses that armament and everyone knows hot rubber is very pliable. Maybe I'm just looking too deep laugh
Luffy's techniques are actually pretty clever. Gear 2nd was explained to be an enhancement of bloodcirculation to ensure a better oxygen administration leading to a higher energy output muscle- and brain-wise. It's just like an engine that will heat up if you increase its performance.
The rubber-armament-thing is something called "vulcanization" in chemistry. It's a chemical process to increase durability and resistance of rubber to mechanical forces.
About the chapter: I really liked how Luffy truly advanced his fighting style by using his defense to directly counterattack. The maincharacter didn't get a simple powerup out of the blue like in other series, but rather refined his current fighting style.
I'm pretty curious to what his response will be, but I'm afraid you're right and he'll simply refuse. Quite sad considering how awesome this team-up could be...
Let's hope he'll agree!