So I guess that was it... What we've seen till now was the full extent of Sanji's power. Which makes sense, given how he was in situations where he would've brought out any hidden powerup he might've been saving multiple times, but he didn't. 
This was how strong he was able to get by running for two years(which is still impressive though).

Luffy in the latest chapter said that he couldn't get the suit to work and that it might be designed only for Sanji, so that almost confirms that this is going to be Sanji's new powerup. I was maybe half expecting that Usopp could use something like that to get a buff like nami but I guess that's out of the picture.

So the powerup Sanji will get is this suit. Honestly, if that is indeed the case then I'm not too happy about it but still it's fine by me. it just adds to the versatility of the crew and who knows, maybe we'll see him doing something cool. 