It is not noticeably wider, if it is it is within a 32nd of an inch, or a millimetre of normal chain.
I have had great ,luck with Tsubaki, the only ones I would run is it, or the strong Diamond series, Hondaman has talked about.
If the sideplates were like 2mm and the added 20 %, it would be 19 thou per side, giving less than a mm increase is what Tsubaki is talking about. They may also mean increase over standard min sideplate thickness + using higher tensile material . The QR refers to the pin being peened in 4 spots, rather than 2, after the chain is aseembled.. which is much stronger..